Global warming has nothing to do with present conservancy problems; it is neglect and poor maintenance of the infrastructure
Posted By Stabroek staff On June 17, 2009 @ 5:04 am In Letters | 2 Comments
http://www.stabroeknews.com/2009/letters/06/17/global-warming-has-nothing-to-do-with-present-conservancy-problems-it-is-neglect-and-poor-maintenance-of-the-infrastructure/
Dear Editor,
Reference is made to a letter in SN by Charles Sohan on the subject of the Ministry of Agriculture cherry-picking items from the proposed Conservancy Adaptation Works study for their Cunha project (‘The Ministry of Agriculture cannot cherry-pick elements from the Conservancy Adaptation Works project because it will not fulfuil the aim of reducing the country’s vulnerability to flooding,’ June 11).
Since 1990 to date numerous studies have been carried out by various foreign consultants in conjunction with local consultants on the EDWC, and despite the government spending vast sums of borrowed money, there is no end in sight for at least one of these consultants to come up with something concrete to end the drainage problems experienced over the years in the EDWC.
In 2004 the government against my advice spent over US$5.0M to raise the conservancy dam by 4 feet in order to increase storage capacity of the reservoir. This in my opinion precipitated the disastrous 2005 flood as the original dam built in 1879 was on a pegasse foundation and removing the vegetation and topsoil that holds the dam material together and then placing an additional load of nearly 500lbs per square foot weakened the strength of the dam appreciably.
Since then there were reports of more spending to raise other sections of the dam as well as carrying out all kinds of work related to strengthening of the EDWC.
I was also made to understand that the US$42M loan obtained by the government some 4 years ago to maintain the nine Declared Drainage and Irrigation Areas throughout the country was also spent on the conservancy. I am not sure if this is correct. The first tender for the D&I areas came in about US$6.0M above the engineer’s estimate, and after revising the quantum of work and re-tendering on 2 further occasions this vital work was abandoned, leaving the declared D&I areas not being maintained for over 30 years.
Now the government, against the advice of myself and other engineers, has decided to pursue the controversial Hope High Level Canal Project recommended by two foreign experts at a cost of some US$15M plus, and now also wants to resuscitate the Cunha drainage outlet which was abandon in the ’60s after Land of Canaan sluice was built.
One of the foreign experts would also be doing further studies to coincide with the Hope Canal outlet. In the DC dated 16.6.09 it was reported that foreign experts would be submitting an up-to-date report on their findings shortly.
In an earlier letter I suggested how the government should pursue this problem, but they are reticent to do so and keep listening to local and foreign experts’ advice who have had little or no experience in the construction, operation and maintenance of a low-level reservoir whose dam is built on a poor foundation material.
In 1966-67 there was a major breach in the conservancy dam at Flagstaff due to the inept drawdown of the reservoir. I was attached to the Hydraulics Division at the time and was responsible along with the Bookers staff on site for sealing the breach.
Some time after this the government received over US$350M in additional revenue due to the rocketing price of sugar on the world market. The government then decided to adopt the Jagan mantra of nationalization of the sugar industry; it had already nationalized the bauxite industry. The Water Commissioners employed by Bookers who were responsible for operating and maintaining the reservoir decided to keep a low profile awaiting nationalization.
Of course, we all know today the present state of these 2 industries and their impact on the nation’s economy. The EDWC has also suffered not being maintained for over 40 years.
Fixing the conservancy in my opinion will be a very costly exercise as well as a continuous drain on government’s limited resources in the years to come. Decommissioning the conservancy will be equally costly and may involve relocation of a section of the population.
A similar situation exists with the general drainage on the coastlands. It took the previous government only 12 years after independence to destroy the institution inherited from the British.
There is no longer a hydrographic section nor a properly functioning hydro-met section. These sections provided valuable information to hydraulic engineers to design engineering works. Today everything is based on guesswork, dig a drain here and there and move pumps around hoping to alleviate the flooding problem. There is also no functioning Hydraulics Division or a viable force account workers section that can respond to any emergency. The division also has been relegated to a few engineers dealing with the sea defences only. Even the sea defence map, which contained over 30 years of invaluable sea defence foreshore erosion data information was destroyed in 1987 when the Hydraulics Division was relocated to Durban Street. The map was left on the ground and rain fell and destroyed the map. I do not believe climate change or global warming has anything to do with the present conservancy problems as postulated recently by the President, just sheer neglect and poor maintenance of the entire infrastructure works including the sea defences over the years. The poor state of the infrastructure works was brought to the government’s attention when they came to power 17 years ago and instead of correcting the problems as promised, the infrastructure was allowed to deteriorate further to its present alarming rate.
Yours faithfully,
M. Alli
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Showing posts with label Hope Canal. Show all posts
Showing posts with label Hope Canal. Show all posts
Wednesday, June 17, 2009
Wednesday, April 22, 2009
Commentary Hope Relief Canal.
Commentary Hope Relief Canal.
By Tony Vieira [April 2009]
There are a numerous facts about the proposed Hope relief canal and the structure which has to be built to pass the lama water through the sea wall to the Atlantic Ocean which require an explanation by the authorities. Since a lot of us do not see this as a viable project.
First of all we have Mott Mc Donald along with CEMCO/SRKN’gineering as the contractors which will do the design of the canal which has to be built to remove excess water from the conservancy during periods of heavy rainfall.
There are four problems with the information in this first paragraph 1. CEMCO was not one of the bidders for this contract, Mott Mc Donald and SRKN’gineering and E&A Consultants were. Now ladies and gentlemen since CEMCO were not bidders in this contract, how is it possible that they end up as being one of the companies which was awarded this huge contract of 56.4 million dollars!
Secondly if the original contract had deficiencies, and was offered again for tendering so that CEMCO could win the contract, how can it be that no one knew about it?
Thirdly Mr Ravi Narine who was the chairman of the D&I board until last year is the major shareholder in SRKN’geneering its an abbreviation of Steve, S; Ravi, R; and Krisna K; Narine N; SRKN then ‘geenering thus SRKN’geenering, whilst Ravi Narine was chairman of the Drainige and Irrigation Board of Guyana his company was getting contracts to do civil engineering works in drainage and irrigation and sea defences for the government in this country and at least one of those contracts for 90 million dollars was an emergency work in East Berbice which did not go through the tender process. In other words we had in this country a chairman of the national drainage board who had an engineering company which benefited from the failure of national infrastructure, and no one in this country ever questioned it except me. And when I did, no one paid attention.
Fourthly Mott Mc Donald is a consulting company which the government hires to advise them on civil engineering matters; as recently as 2007 Mott Mc Donald was advising the government on how to design and maintain our drainage system, how can this company which the government relies on to tell them how to design our systems end up as a contractor actually being paid to design this canal and to tell us how it must be constructed to relieve the high water level of the Lama conservancy, is this not a conflict of interest? This company advises us on what to do, then we allow them to bid on doing it?
Having gotten over these 4 obstacles to the project we then see a letter to the newspaper telling the government that their current Chairman of the National Drainage and Irrigation Board does not know what he is talking about, since he has publicly declared that this new relief canal must be designed to withstand a 10,000 year storm i.e. a storm which only comes every 10,000 years! Now ladies and gentlemen Messers Ralph V. Seegobin and Ram Dharamdial have rightly pointed out in their letter to the newspaper dated April 8th 2009 that it would be impossible to design any system for such a storm since data would have had to be available before Columbus discovered the new world in 1492, 517 years ago duhhhh…. Lionel; so it would be impossible to have records going back 5,000 years.
Before I go further I would like to put into perspective for you what this canal will entail, we will have running from the conservancy a canal which has embankments at nearly 59 GD high on both banks i.e. Higher than the highest high tide we ever had in this country which was 57.3 ft. GD running from south to north for nearly 12 miles from the conservancy to the Atlantic ocean and it would have to be wide at least 100-40 ft wide. The land level in most of this area from the conservancy to the Atlantic would be about 50/52 ft. GD. So the banks and the water running from the conservancy to the Atlantic Ocean for 8 miles would be 8-9 ft higher than the surrounding terrain.
This year in February I asked a question in parliament about the lama levels during the month of December 2008 and January 2009 including the levels of the Land of Canaan relief on the East Bank.
The relief structure at Land of Canaan is 40 ft wide but the bottom [the floor] is not as low as our normal kokers it is at around 54 GD so this structure is a weir and not a koker at all. The normal koker level at the bottom i.e. the invert level is usually 44 to 45 GD, 10 feet deeper.
The information presented to me suggested that all through January 2009 the water level at Land of Canaan was 2 ft lower than in the conservancy; it was 56 ft. GD compared to 58 ft. GD, this means to me that this relief is only working at 50% of its capacity, if we can deliver more water to Land Of Canaan we can double the discharge rate of the outlet to the Demerara River and if we changed it from a 40 wide weir, to a 40 ft wide x 10 ft deep multiple koker structure we would have a 400 foot wide aperture to the Demerara river i.e. we would be able to discharge nearly 20 times the current amount of water to the Demerara river.
One engineer tells me that the water level at the northern dam of the conservancy which runs parallel to the east coast road is higher than the water at the back end of the conservancy I am saying that this is nonsense since the water coming into the conservancy and causing so much damage is coming from the highlands at Timehri and as far back as Saint Cuthbert Mission [see map] since both the Lama and Maduni creeks empty water from these highlands into the back or southern end of the conservancy, the reason why the back end of the conservancy has a lower average water level than the front or northern end of the conservancy is that we are blowing quite a bit of the water at Land of Canaan but clearly we are not blowing enough hence the level in the front is high.
Relieving this high level of water at Land of Canaan at the western end of the conservancy would be far more effective since the discharge canal would be a fraction of the length than that which would be required to bring it to the Atlantic to the north and it would be safer than removing the high Lama level through a new high level trench at Hope.
Building a koker of any kind to the Ocean is far, far more expensive than building it to a river the tide action alone makes it a very expensive proposition to build maintain and operate.
Additionally even if there is reason why this Hope project should go ahead it is my firm belief that the trench delivering the lama water to the Land of Canaan Relief should be examined very closely and widened so that its efficiency can be enhanced, after all ladies and gentlemen if the water level in the conservancy is 58 GD and the water level at Land of Canaan is 56 GD then there is a two foot drop in a canal of less than one and a half miles reducing its effectiveness considerably.
But essentially all rational thought would prompt any intelligent person to conclude that the major Lama relief should be at land of Canaan, first the one and a half mile feeder trench from Land of Canaan to the conservancy which has been there since the 60’s and could be as wide as we want it to be since the population there is much less than on the East Coast is already there; secondly it would be far shorter run than the proposed approximately 10-12 mile canal which will terminate at Hope and therefore it would not cost anywhere near 3 billion dollars; thirdly the cost of constructing relief structures to the Demerara river would be far less than similar construction to the Atlantic; fourthly the surrounding land level at Land of Canaan is nearly 4 ft higher than the run from the conservancy to Hope on the East coast thus it would have the potential to be less of a menace in case of a breach.
Really ladies and gentlemen I can’t under the circumstances agree to this situation at all and every engineer I have expressed this view to agrees with me. This project is looking more and more as one to put money in someone’s pocket rather than a realistic and cost effective solution to a real and dangerous problem.
The government must be aware that this project is now riddled with controversy and that there is significant data to suggest that it is not a viable project. Obviously since there are so many plusses to this relief being sighted at Land of Canaan, we have to conclude that some person or persons have an agenda which is militating against doing this job in the most cost effective and safe manner.
By Tony Vieira [April 2009]
There are a numerous facts about the proposed Hope relief canal and the structure which has to be built to pass the lama water through the sea wall to the Atlantic Ocean which require an explanation by the authorities. Since a lot of us do not see this as a viable project.
First of all we have Mott Mc Donald along with CEMCO/SRKN’gineering as the contractors which will do the design of the canal which has to be built to remove excess water from the conservancy during periods of heavy rainfall.
There are four problems with the information in this first paragraph 1. CEMCO was not one of the bidders for this contract, Mott Mc Donald and SRKN’gineering and E&A Consultants were. Now ladies and gentlemen since CEMCO were not bidders in this contract, how is it possible that they end up as being one of the companies which was awarded this huge contract of 56.4 million dollars!
Secondly if the original contract had deficiencies, and was offered again for tendering so that CEMCO could win the contract, how can it be that no one knew about it?
Thirdly Mr Ravi Narine who was the chairman of the D&I board until last year is the major shareholder in SRKN’geneering its an abbreviation of Steve, S; Ravi, R; and Krisna K; Narine N; SRKN then ‘geenering thus SRKN’geenering, whilst Ravi Narine was chairman of the Drainige and Irrigation Board of Guyana his company was getting contracts to do civil engineering works in drainage and irrigation and sea defences for the government in this country and at least one of those contracts for 90 million dollars was an emergency work in East Berbice which did not go through the tender process. In other words we had in this country a chairman of the national drainage board who had an engineering company which benefited from the failure of national infrastructure, and no one in this country ever questioned it except me. And when I did, no one paid attention.
Fourthly Mott Mc Donald is a consulting company which the government hires to advise them on civil engineering matters; as recently as 2007 Mott Mc Donald was advising the government on how to design and maintain our drainage system, how can this company which the government relies on to tell them how to design our systems end up as a contractor actually being paid to design this canal and to tell us how it must be constructed to relieve the high water level of the Lama conservancy, is this not a conflict of interest? This company advises us on what to do, then we allow them to bid on doing it?
Having gotten over these 4 obstacles to the project we then see a letter to the newspaper telling the government that their current Chairman of the National Drainage and Irrigation Board does not know what he is talking about, since he has publicly declared that this new relief canal must be designed to withstand a 10,000 year storm i.e. a storm which only comes every 10,000 years! Now ladies and gentlemen Messers Ralph V. Seegobin and Ram Dharamdial have rightly pointed out in their letter to the newspaper dated April 8th 2009 that it would be impossible to design any system for such a storm since data would have had to be available before Columbus discovered the new world in 1492, 517 years ago duhhhh…. Lionel; so it would be impossible to have records going back 5,000 years.
Before I go further I would like to put into perspective for you what this canal will entail, we will have running from the conservancy a canal which has embankments at nearly 59 GD high on both banks i.e. Higher than the highest high tide we ever had in this country which was 57.3 ft. GD running from south to north for nearly 12 miles from the conservancy to the Atlantic ocean and it would have to be wide at least 100-40 ft wide. The land level in most of this area from the conservancy to the Atlantic would be about 50/52 ft. GD. So the banks and the water running from the conservancy to the Atlantic Ocean for 8 miles would be 8-9 ft higher than the surrounding terrain.
This year in February I asked a question in parliament about the lama levels during the month of December 2008 and January 2009 including the levels of the Land of Canaan relief on the East Bank.
The relief structure at Land of Canaan is 40 ft wide but the bottom [the floor] is not as low as our normal kokers it is at around 54 GD so this structure is a weir and not a koker at all. The normal koker level at the bottom i.e. the invert level is usually 44 to 45 GD, 10 feet deeper.
The information presented to me suggested that all through January 2009 the water level at Land of Canaan was 2 ft lower than in the conservancy; it was 56 ft. GD compared to 58 ft. GD, this means to me that this relief is only working at 50% of its capacity, if we can deliver more water to Land Of Canaan we can double the discharge rate of the outlet to the Demerara River and if we changed it from a 40 wide weir, to a 40 ft wide x 10 ft deep multiple koker structure we would have a 400 foot wide aperture to the Demerara river i.e. we would be able to discharge nearly 20 times the current amount of water to the Demerara river.
One engineer tells me that the water level at the northern dam of the conservancy which runs parallel to the east coast road is higher than the water at the back end of the conservancy I am saying that this is nonsense since the water coming into the conservancy and causing so much damage is coming from the highlands at Timehri and as far back as Saint Cuthbert Mission [see map] since both the Lama and Maduni creeks empty water from these highlands into the back or southern end of the conservancy, the reason why the back end of the conservancy has a lower average water level than the front or northern end of the conservancy is that we are blowing quite a bit of the water at Land of Canaan but clearly we are not blowing enough hence the level in the front is high.
Relieving this high level of water at Land of Canaan at the western end of the conservancy would be far more effective since the discharge canal would be a fraction of the length than that which would be required to bring it to the Atlantic to the north and it would be safer than removing the high Lama level through a new high level trench at Hope.
Building a koker of any kind to the Ocean is far, far more expensive than building it to a river the tide action alone makes it a very expensive proposition to build maintain and operate.
Additionally even if there is reason why this Hope project should go ahead it is my firm belief that the trench delivering the lama water to the Land of Canaan Relief should be examined very closely and widened so that its efficiency can be enhanced, after all ladies and gentlemen if the water level in the conservancy is 58 GD and the water level at Land of Canaan is 56 GD then there is a two foot drop in a canal of less than one and a half miles reducing its effectiveness considerably.
But essentially all rational thought would prompt any intelligent person to conclude that the major Lama relief should be at land of Canaan, first the one and a half mile feeder trench from Land of Canaan to the conservancy which has been there since the 60’s and could be as wide as we want it to be since the population there is much less than on the East Coast is already there; secondly it would be far shorter run than the proposed approximately 10-12 mile canal which will terminate at Hope and therefore it would not cost anywhere near 3 billion dollars; thirdly the cost of constructing relief structures to the Demerara river would be far less than similar construction to the Atlantic; fourthly the surrounding land level at Land of Canaan is nearly 4 ft higher than the run from the conservancy to Hope on the East coast thus it would have the potential to be less of a menace in case of a breach.
Really ladies and gentlemen I can’t under the circumstances agree to this situation at all and every engineer I have expressed this view to agrees with me. This project is looking more and more as one to put money in someone’s pocket rather than a realistic and cost effective solution to a real and dangerous problem.
The government must be aware that this project is now riddled with controversy and that there is significant data to suggest that it is not a viable project. Obviously since there are so many plusses to this relief being sighted at Land of Canaan, we have to conclude that some person or persons have an agenda which is militating against doing this job in the most cost effective and safe manner.
Saturday, February 28, 2009
The inherent core problem of the conservancy is not being addressed
The inherent core problem of the conservancy is not being addressed
Posted By Stabroek staff On February 27, 2009 @ 5:07 am In Letters | 3 Comments
Dear Editor,
We refer to Mr Seegobin’s letter (‘Risk analysis study for conservancy relief absolutely needed,’ SN 24.2.09) on the Hope Canal Project and recommend that he forward his concerns to the Government of Guyana for a risk analysis of the conservancy dikes and flooding which should be carried out.
In SN dated 24.2.09 the Minister of Agriculture stated that modelling for the conservancy was earlier carried out by a British and a Dutch company and they recommended that Hope is the acceptable location. Earlier in another article he stated that the water depth was higher at the Hope end and was lower at Land of Canaan end, hence the decision to locate the canal at Hope. He also said it was not necessary to fix the Land of Canaan Sluice (LOC) and canal to drain the conservancy more efficiently as recommended by one of the writers in an earlier letter. Another consultant is presently undertaking a further study of the conservancy costing some US$3.8M.
As experienced engineers who both worked in drainage and irrigation and sea defence sectors including the conservancy for a number of years, we are surprised at the approach adopted. Study after study is being carried out, yet the inherent core problem of the conservancy is not being fully addressed and there has not been any published report of the studies undertaken so far.
The canal size we mentioned in our letter was a preliminary example we roughly designed based on the 2000 cusecs capacity of the LOC relief canal. This was merely to give a perspective of the scale the hydraulic works contemplated.
We reiterate our position that unless this Hope Canal is designed to work 24 hours a day and can operate as such it will eventually become a white elephant.
It should also be noted, the discharge outlet sluice for the Hope Canal would be located through a section of the existing coastal sea wall that is over 80 years old. No proper sea defence alignment has been worked out for this area. Maintaining the existing wall during a future severe coastal erosion cycle is doubtful. We recognize that the risk and hydraulic uncertainty is very high and becomes the main limitation of constructing a major discharge structure through the existing sea wall.
Yours faithfully,
Malcolm Alli P Eng
Michael Ragwen P Eng
Posted By Stabroek staff On February 27, 2009 @ 5:07 am In Letters | 3 Comments
Dear Editor,
We refer to Mr Seegobin’s letter (‘Risk analysis study for conservancy relief absolutely needed,’ SN 24.2.09) on the Hope Canal Project and recommend that he forward his concerns to the Government of Guyana for a risk analysis of the conservancy dikes and flooding which should be carried out.
In SN dated 24.2.09 the Minister of Agriculture stated that modelling for the conservancy was earlier carried out by a British and a Dutch company and they recommended that Hope is the acceptable location. Earlier in another article he stated that the water depth was higher at the Hope end and was lower at Land of Canaan end, hence the decision to locate the canal at Hope. He also said it was not necessary to fix the Land of Canaan Sluice (LOC) and canal to drain the conservancy more efficiently as recommended by one of the writers in an earlier letter. Another consultant is presently undertaking a further study of the conservancy costing some US$3.8M.
As experienced engineers who both worked in drainage and irrigation and sea defence sectors including the conservancy for a number of years, we are surprised at the approach adopted. Study after study is being carried out, yet the inherent core problem of the conservancy is not being fully addressed and there has not been any published report of the studies undertaken so far.
The canal size we mentioned in our letter was a preliminary example we roughly designed based on the 2000 cusecs capacity of the LOC relief canal. This was merely to give a perspective of the scale the hydraulic works contemplated.
We reiterate our position that unless this Hope Canal is designed to work 24 hours a day and can operate as such it will eventually become a white elephant.
It should also be noted, the discharge outlet sluice for the Hope Canal would be located through a section of the existing coastal sea wall that is over 80 years old. No proper sea defence alignment has been worked out for this area. Maintaining the existing wall during a future severe coastal erosion cycle is doubtful. We recognize that the risk and hydraulic uncertainty is very high and becomes the main limitation of constructing a major discharge structure through the existing sea wall.
Yours faithfully,
Malcolm Alli P Eng
Michael Ragwen P Eng
When considering the Hope Canal the government should take into account canal failures elsewhere in Guyana
When considering the Hope Canal the government should take into account canal failures elsewhere in Guyana
Posted By Stabroek staff On February 28, 2009 @ 5:03 am In Letters | 5 Comments
Dear Editor,
I have perused letters from Messrs Malcom Ali, Ragwin, C Sohan and R Seegobin. These engineers, particularly Malcom are all expressing their valuable opinion on flood relief for the EDWC. However, I am not sure whether the average Guyanese comprehends whether the Hope Canal is technically feasible or not. I am not entering a technical discourse on risk analysis, etc, but hopefully will bring to the average person basic and common-sense detail that ought to be a factor in the construction of Hope relief canal. In doing so, I would like to draw their attention as to how functional some existing drainage canals are, hoping some lessons can be learnt for the proposed Hope Canal.
Firstly, Canals No 1 and 2 in West Demerara. The Canals Polder is supposed to be drained by two major canals about 7 miles long, which are tidally controlled at the outlet. In spite of this, the Canals Polder floods incessantly. The farming community has never escaped inundation during significant rainfalls. The reason is that input (rainfall) less the natural losses, exceeds the output (sluice discharges), hence there are accumulations (flooding). Assuming that the canals are perfectly maintained, a flood wave emanating from the top of the catchment would have to travel at a speed that would erode the channel to reach the sluice. This does not happen as the canals are designed to flow at a velocity of 3 ft per second. The actual velocity is much lower since the canals are poorly maintained, and the velocity is checked by the weeds and sediment in the canals. Let us be conservative and say that the canals presently flow at the designed velocity. With that rate of movement of water, it will take more than 10 hours for the headwater to be conveyed. Considering that the average time the sluice opens at low tide to be 4 hours, the headwater would not reach the Demerara in time. This results in a backwater effect in the canals, resulting in the ponding and stagnation of water. Because the canals are not delivering the water in sufficient quantity, the sluices operate below capacity. Hence, we can conclude that the flooding in the polders is partly due to the lack of adequate conveyance.
The Naamryck canal is another example of a channel poorly conveying water. Naamryck is also long (4+ miles) and is controlled by spillway/gates that discharge into the Essequibo River. Like the Canals Polder, the Naamryck outfall is likewise discharging below capacity, and flooding ensues. In December 1987, when the Boeraserie Conservancy was overtopping, Naamryck was used as the relief. The government engineer of West Demerara said that the water was not moving fast enough through the canal to the spillway outlet, and there was extensive flooding due to the accumulation. Input did not equal output.
The canal leading to the two pumps at Onverwagt is an interesting case study. The two pumps at Onverwagt are part of the MMA flood relief infrastructure. The pumps are meant to be fed with a fairly wide and deep channel that drains a part of the MMA. I observed that these two pumps have a discharge capacity in excess of the rate at which the channel is capable of delivering the flows. I made those observations when I tested those pumps for hydraulic efficiency in 1982. I realised then that only one of those pumps could have been tested over a 2-hour cyclic period as the pumps were cutting off due to starvation. This means that water was not reaching the pumps fast enough via the canal. It was determined that about 2 hours was required to allow the flows to re-accumulate in the reach of the canal immediately upstream of the pumping station, hence the 2 hour cycle was chosen. I concluded in my report to the then Hydraulics Division that the canal could not deliver the water required for even a single pump to operate on a continuous basis. (A major problem that had to be considered in the conveyance of the canal is the rapid drawdown of the water level in the channel, which caused the banks to fail.)
Another example is the failure of the conveyance channel to provide flood relief to my native village. I grew up in Meten Meer Zorg, and frequently woke up to the villages flooded with overnight rain. The flood relief was again a sluice discharging into the Atlantic. I vividly remember that the discharge at the sluice never appeared to be at capacity in spite of the fact that the village is knee-deep in water. I later understood the reason. Simply, the floodwater was never conveyed efficiently to the sluice to be discharged during low tide periods as there is a travel time required to move floods to the sluice. Obviously, MMZ flooded because the required travel time for the flood waves exceeded the hours that the sluice could remain open, so like all other villagers, I waited on the next low tide. In the meantime, there was a build-up of water, backwater effects were created in the trench and increases in accumulations occurred.
What lesson can we learn from the above mentioned examples of drainage canals failure to convey the floods to the outfalls? Liliendaal and Anna Regina are other examples. Knowing that the discharges for the Hope Canal could take 2 to 3 days to travel the length of the proposed canal to the Atlantic, the outflows/discharges would be tidally influenced, and given the above four examples of flooding attributed to travel time (conveyance) failures, do Guyanese have hope that the Hope Canal would function effectively? The Guyanese public is eager to know that the government engineer/consultant knows the answer before they begin to spend $3B.
I acknowledge Mr C Sohan for recognising the conveyance problem. You may recall that he said, “It is estimated that floodwater from critical parts of the EDWC could take from 24-48 hours to reach any one of the relief sluices” (SN February 9), in his review of the Hope Canal proposition. For Hope to function, a steady state condition has to be created, where output from the conservancy can be equal to the output at the sluice gates. But for this idealized situation to happen, the coordination between the release at the conservancy and the discharge has to be continuous beyond the time the tide allows the sluices to open. The proliferation of weeds, bank failures and sediment deposition would create imbalances that would affect the desired steady-state conditions. Let us not build another Canals Polder, Naamryck, or Onverwagt canal.
Yours faithfully,
Ram Dharamdial
5 Comments (Open | Close)
5 Comments To "When considering the Hope Canal the government should take into account canal failures elsewhere in Guyana"
#1 Comment By M. Xiu Quan-Balgobind-Hackett (-214) On February 28, 2009 @ 8:25 am
Thanks, Mr. Dharamdial. You have the rare gift of explaining a difficult concept to the layman, the non-intuitive differences between moving water and stationary water. Keep it up.
#2 Comment By michael tannassee On February 28, 2009 @ 9:09 am
….. Ram’s missive is concise as far as his theories of input that will always be more than the output is able to handle ,, regardless of where the output is located ,, unless the output is made to flow twenty four seven (24/7)… and that would have to be done by two canals from just below the EDWC to the Berbice and Demerara rivers ,,
and they MUST be engineered to flow 24/7,,,, 24/7 ,,, 24/7 ,, 24/7,,,, TWO CANALS ,, FROM JUST BELOW de EDWC to de BERBICE an de DEMERARA RIVERS ,,, an mek shor ahyuh dig am fuh watah flo all de time,,,, day an nite ,, if ahyuh want fuh live whey ahyuh ah live now ,, in comfort ! but meh still ah seh ahyuh gon gat to move caz de canals to the two rivers named above is onle TEMPORARY !!!! juss remebah dah !…….
#3 Comment By Ralph Seegobin On February 28, 2009 @ 12:38 pm
You are quite correct in your reasoning. If we forget the past we are bound to repeat it. The canal apart from conveyance is also storing water (the backwater as you mention) for release through the sluice for the next tide. All valid inputs for the model including the canal efficiency and time it takes water to travel to its discharge destination. My current work responsibility includes seek out information from the clients maintenance group to incorporate into our design. Sometimes we cannot incorporate all their requirements but the maintenance is made aware of special needs of the project. Numerous model scenarios can be developed and the shortcoming of each can be examined. Again this is no playing ground for experiment. Am sure the MoA/NDIA are reading. We can design the best working hydrological model but what about the management of the reservoir in particular forcasting. The reservoir must be able to release water and to recapture water from forecasted rainfall. How good is the weather forcasting?
#4 Comment By caesar agustus On February 28, 2009 @ 2:05 pm
The only use of this hopeless canal is that it is hopelessly useless for draining below sea level,hopeless because the sea is higher than the canal,will be useful for the number of persons who will be drowned in it,a maintainance nightmare,and a burden on taxpayers,not politicians.And, another excuse for politicians to gloat over “i did this and that.” Get rid of this canal idea.
#5 Comment By Sarkar On February 28, 2009 @ 2:51 pm
Exactly! Forecasting is of utmost importance (remember when everyday the forecast was ‘fair to cloudy, with a few scattered showers’? Just revisit Justin Concern). This is not the end…. Who will interpret the forecast? Who will be responsible enough to understand when flow at inlet must be reduced or enhanced, in other words where is the responsible management? Point taken! I need not mention what happened at Mahaica creek. You must remember if the canal is to be used for storage then sedimentation follows. Flow design must be the key for efficiency.
Article printed from Stabroek News: http://www.stabroeknews.com
URL to article: http://www.stabroeknews.com/2009/letters/02/28/when-considering-the-hope-canal-the-government-should-take-into-account-canal-failures-elsewhere-in-guyana/
Posted By Stabroek staff On February 28, 2009 @ 5:03 am In Letters | 5 Comments
Dear Editor,
I have perused letters from Messrs Malcom Ali, Ragwin, C Sohan and R Seegobin. These engineers, particularly Malcom are all expressing their valuable opinion on flood relief for the EDWC. However, I am not sure whether the average Guyanese comprehends whether the Hope Canal is technically feasible or not. I am not entering a technical discourse on risk analysis, etc, but hopefully will bring to the average person basic and common-sense detail that ought to be a factor in the construction of Hope relief canal. In doing so, I would like to draw their attention as to how functional some existing drainage canals are, hoping some lessons can be learnt for the proposed Hope Canal.
Firstly, Canals No 1 and 2 in West Demerara. The Canals Polder is supposed to be drained by two major canals about 7 miles long, which are tidally controlled at the outlet. In spite of this, the Canals Polder floods incessantly. The farming community has never escaped inundation during significant rainfalls. The reason is that input (rainfall) less the natural losses, exceeds the output (sluice discharges), hence there are accumulations (flooding). Assuming that the canals are perfectly maintained, a flood wave emanating from the top of the catchment would have to travel at a speed that would erode the channel to reach the sluice. This does not happen as the canals are designed to flow at a velocity of 3 ft per second. The actual velocity is much lower since the canals are poorly maintained, and the velocity is checked by the weeds and sediment in the canals. Let us be conservative and say that the canals presently flow at the designed velocity. With that rate of movement of water, it will take more than 10 hours for the headwater to be conveyed. Considering that the average time the sluice opens at low tide to be 4 hours, the headwater would not reach the Demerara in time. This results in a backwater effect in the canals, resulting in the ponding and stagnation of water. Because the canals are not delivering the water in sufficient quantity, the sluices operate below capacity. Hence, we can conclude that the flooding in the polders is partly due to the lack of adequate conveyance.
The Naamryck canal is another example of a channel poorly conveying water. Naamryck is also long (4+ miles) and is controlled by spillway/gates that discharge into the Essequibo River. Like the Canals Polder, the Naamryck outfall is likewise discharging below capacity, and flooding ensues. In December 1987, when the Boeraserie Conservancy was overtopping, Naamryck was used as the relief. The government engineer of West Demerara said that the water was not moving fast enough through the canal to the spillway outlet, and there was extensive flooding due to the accumulation. Input did not equal output.
The canal leading to the two pumps at Onverwagt is an interesting case study. The two pumps at Onverwagt are part of the MMA flood relief infrastructure. The pumps are meant to be fed with a fairly wide and deep channel that drains a part of the MMA. I observed that these two pumps have a discharge capacity in excess of the rate at which the channel is capable of delivering the flows. I made those observations when I tested those pumps for hydraulic efficiency in 1982. I realised then that only one of those pumps could have been tested over a 2-hour cyclic period as the pumps were cutting off due to starvation. This means that water was not reaching the pumps fast enough via the canal. It was determined that about 2 hours was required to allow the flows to re-accumulate in the reach of the canal immediately upstream of the pumping station, hence the 2 hour cycle was chosen. I concluded in my report to the then Hydraulics Division that the canal could not deliver the water required for even a single pump to operate on a continuous basis. (A major problem that had to be considered in the conveyance of the canal is the rapid drawdown of the water level in the channel, which caused the banks to fail.)
Another example is the failure of the conveyance channel to provide flood relief to my native village. I grew up in Meten Meer Zorg, and frequently woke up to the villages flooded with overnight rain. The flood relief was again a sluice discharging into the Atlantic. I vividly remember that the discharge at the sluice never appeared to be at capacity in spite of the fact that the village is knee-deep in water. I later understood the reason. Simply, the floodwater was never conveyed efficiently to the sluice to be discharged during low tide periods as there is a travel time required to move floods to the sluice. Obviously, MMZ flooded because the required travel time for the flood waves exceeded the hours that the sluice could remain open, so like all other villagers, I waited on the next low tide. In the meantime, there was a build-up of water, backwater effects were created in the trench and increases in accumulations occurred.
What lesson can we learn from the above mentioned examples of drainage canals failure to convey the floods to the outfalls? Liliendaal and Anna Regina are other examples. Knowing that the discharges for the Hope Canal could take 2 to 3 days to travel the length of the proposed canal to the Atlantic, the outflows/discharges would be tidally influenced, and given the above four examples of flooding attributed to travel time (conveyance) failures, do Guyanese have hope that the Hope Canal would function effectively? The Guyanese public is eager to know that the government engineer/consultant knows the answer before they begin to spend $3B.
I acknowledge Mr C Sohan for recognising the conveyance problem. You may recall that he said, “It is estimated that floodwater from critical parts of the EDWC could take from 24-48 hours to reach any one of the relief sluices” (SN February 9), in his review of the Hope Canal proposition. For Hope to function, a steady state condition has to be created, where output from the conservancy can be equal to the output at the sluice gates. But for this idealized situation to happen, the coordination between the release at the conservancy and the discharge has to be continuous beyond the time the tide allows the sluices to open. The proliferation of weeds, bank failures and sediment deposition would create imbalances that would affect the desired steady-state conditions. Let us not build another Canals Polder, Naamryck, or Onverwagt canal.
Yours faithfully,
Ram Dharamdial
5 Comments (Open | Close)
5 Comments To "When considering the Hope Canal the government should take into account canal failures elsewhere in Guyana"
#1 Comment By M. Xiu Quan-Balgobind-Hackett (-214) On February 28, 2009 @ 8:25 am
Thanks, Mr. Dharamdial. You have the rare gift of explaining a difficult concept to the layman, the non-intuitive differences between moving water and stationary water. Keep it up.
#2 Comment By michael tannassee On February 28, 2009 @ 9:09 am
….. Ram’s missive is concise as far as his theories of input that will always be more than the output is able to handle ,, regardless of where the output is located ,, unless the output is made to flow twenty four seven (24/7)… and that would have to be done by two canals from just below the EDWC to the Berbice and Demerara rivers ,,
and they MUST be engineered to flow 24/7,,,, 24/7 ,,, 24/7 ,, 24/7,,,, TWO CANALS ,, FROM JUST BELOW de EDWC to de BERBICE an de DEMERARA RIVERS ,,, an mek shor ahyuh dig am fuh watah flo all de time,,,, day an nite ,, if ahyuh want fuh live whey ahyuh ah live now ,, in comfort ! but meh still ah seh ahyuh gon gat to move caz de canals to the two rivers named above is onle TEMPORARY !!!! juss remebah dah !…….
#3 Comment By Ralph Seegobin On February 28, 2009 @ 12:38 pm
You are quite correct in your reasoning. If we forget the past we are bound to repeat it. The canal apart from conveyance is also storing water (the backwater as you mention) for release through the sluice for the next tide. All valid inputs for the model including the canal efficiency and time it takes water to travel to its discharge destination. My current work responsibility includes seek out information from the clients maintenance group to incorporate into our design. Sometimes we cannot incorporate all their requirements but the maintenance is made aware of special needs of the project. Numerous model scenarios can be developed and the shortcoming of each can be examined. Again this is no playing ground for experiment. Am sure the MoA/NDIA are reading. We can design the best working hydrological model but what about the management of the reservoir in particular forcasting. The reservoir must be able to release water and to recapture water from forecasted rainfall. How good is the weather forcasting?
#4 Comment By caesar agustus On February 28, 2009 @ 2:05 pm
The only use of this hopeless canal is that it is hopelessly useless for draining below sea level,hopeless because the sea is higher than the canal,will be useful for the number of persons who will be drowned in it,a maintainance nightmare,and a burden on taxpayers,not politicians.And, another excuse for politicians to gloat over “i did this and that.” Get rid of this canal idea.
#5 Comment By Sarkar On February 28, 2009 @ 2:51 pm
Exactly! Forecasting is of utmost importance (remember when everyday the forecast was ‘fair to cloudy, with a few scattered showers’? Just revisit Justin Concern). This is not the end…. Who will interpret the forecast? Who will be responsible enough to understand when flow at inlet must be reduced or enhanced, in other words where is the responsible management? Point taken! I need not mention what happened at Mahaica creek. You must remember if the canal is to be used for storage then sedimentation follows. Flow design must be the key for efficiency.
Article printed from Stabroek News: http://www.stabroeknews.com
URL to article: http://www.stabroeknews.com/2009/letters/02/28/when-considering-the-hope-canal-the-government-should-take-into-account-canal-failures-elsewhere-in-guyana/
Tuesday, February 24, 2009
Risk analysis study for conservancy relief absolutely needed
Risk analysis study for conservancy relief absolutely needed
Posted By Stabroek staff On February 24, 2009 @ 5:03 am In Letters | 2 Comments
Dear Editor,
The Government of Guyana is undaunted in its decision to discharge the relief structure & canal towards the Atlantic Ocean. Three opinions were expressed via SN’s letter columns: Engineer Charles Sohan agrees with the decision to drain to the Atlantic, Engineers Malcolm Alli & Mike Ragwen are in favour of a discharge to the Demerara River and I (also an Engineer by profession) prefer to let the results from a hydrological model and risk analysis determine the discharge location before spending $3B on the waterway.
My opinion was first published in the SN on 1-31-09 and may not have been totally understood since Engineers Alli and Ragwen were more interested in my modeling capability for low-level lands. It is against this background my response was conceived and will at the same time serve to substantiate my initial letter and hopefully will catch the attention of the relevant policy makers within the Government including the Tender Board.
My experience allows me to write about hydrological modeling as it pertains to the East Demerara Water Conservancy in conjunction with modeling for open conveyance systems (canals). Engineers Alli & Ragwen are of the opinion that ‘modeling for multiple outlets into tidal and non tidal areas is not simple”. I disagree, routing model software have ‘come a far way’ making them competitive, helpful and user friendly. The challenging task is to obtain tidal input data (the tidal cycle) for running the model. The tidal data will never-the-less still be needed to ‘come up with’ the number of doors required for the sluice. An important prediction on the effect of the tidal cycle due to global warming will have to be made. Do we prefer the Atlantic for gravity drainage or pump drainage? What is the operational plan during the dry weather?
I will now substantiate my initial letter. As part of the input parameters for modeling I included the length and cross section of the canals. This was not ‘by guess’. I have anticipated that the software of choice should be able to route the conservancy to the outfall, hence the need to have design information on the proposed and existing canals. The proposed canal (at Hope or Land of Canaan) should serve, at the least, dual functions: increased storage for the conservancy and act as conveyance for flood relief and is an integral part in the conservancy modeling process. I do not expect the consultant to model only the hydraulics of the canal unless (I reiterate) it is a canal design project and the flow is already known.
I did not get into details of risk analysis in my initial letter since it is not my area of expertise but what I did not expect was having engineers seek details about my risk plan specifics and suggesting that if this is rarely used as a management tool in Guyana then it should not be. My answer is simply TWW (Total Wrong Wuk). My position remains, a risk analysis study is required. The risks will eventually summarize costs and costs lead to decision making and approaches for funding. I need not be reminded about the need for dam safety analysis, this is a definite requirement.
My peers also have approximated the size of the canal needed. This I opine is premature, misleading and guesswork, even if they have access to information (reports on the conservancy) that the Government does not. Again I ask “Where are all the old reports from major projects undertaken in British Guiana”?
The Government has openly stated that Hope was the best site for the relief structure. I think they should consider making public the document/evidence that suggests that the Hope Canal is the best option before adventuring into spending $3B or are we launching the first “white” water project (as against white elephant) and I agree with Engineer Sohan that a re-tender should not be ruled out.
Yours faithfully,
Ralph Seegobin
(Professional Engineer)
2 Comments (Open | Close)
2 Comments To "Risk analysis study for conservancy relief absolutely needed"
#1 Comment By Brendan Samaroo On February 24, 2009 @ 6:13 am
Mr. President & Minister of Agriculture would it not make some sense to get all of these gentlemen together sit down and have a meeting with them and hear them out?
Is that too adult a thing for this government to consider?
#2 Comment By Cummins On February 24, 2009 @ 8:24 am
Before I took up a career in global business and policy I was a mechanical engineer. One of the things I learned and understood in undergraduate school and early career is that if engineers are arguing among themselves then nobody in the group knows what they are talking about for engineering is an (almost) exact science. All results and actions should be streaming from a UNIVERSALLY ACCEPTED mathematical formula that was TESTED and PROVEN in a laboratory setting and by prototype model. Apply the wrong formula and the results could be catastrophic and deadly. I find it disheartening that engineers are having a street fight over which formula or method to apply. In business policy we get do-overs, in engineering there are none; take it from me who have practiced in both fields.
Ralph, in the absence of knowing at what level the referenced gentlemen are in their respective careers your PE certification gives you more credibility on this argument as far as I am concerned. I am sensing the other gentlemen are more making a cost decision and we know the rule of engineering is safety first, cost second.
I wish you guys can agree on what formula should be applied.
Article printed from Stabroek News: http://www.stabroeknews.com
URL to article: http://www.stabroeknews.com/2009/letters/02/24/risk-analysis-study-for-conservancy-relief-absolutely-needed/
Posted By Stabroek staff On February 24, 2009 @ 5:03 am In Letters | 2 Comments
Dear Editor,
The Government of Guyana is undaunted in its decision to discharge the relief structure & canal towards the Atlantic Ocean. Three opinions were expressed via SN’s letter columns: Engineer Charles Sohan agrees with the decision to drain to the Atlantic, Engineers Malcolm Alli & Mike Ragwen are in favour of a discharge to the Demerara River and I (also an Engineer by profession) prefer to let the results from a hydrological model and risk analysis determine the discharge location before spending $3B on the waterway.
My opinion was first published in the SN on 1-31-09 and may not have been totally understood since Engineers Alli and Ragwen were more interested in my modeling capability for low-level lands. It is against this background my response was conceived and will at the same time serve to substantiate my initial letter and hopefully will catch the attention of the relevant policy makers within the Government including the Tender Board.
My experience allows me to write about hydrological modeling as it pertains to the East Demerara Water Conservancy in conjunction with modeling for open conveyance systems (canals). Engineers Alli & Ragwen are of the opinion that ‘modeling for multiple outlets into tidal and non tidal areas is not simple”. I disagree, routing model software have ‘come a far way’ making them competitive, helpful and user friendly. The challenging task is to obtain tidal input data (the tidal cycle) for running the model. The tidal data will never-the-less still be needed to ‘come up with’ the number of doors required for the sluice. An important prediction on the effect of the tidal cycle due to global warming will have to be made. Do we prefer the Atlantic for gravity drainage or pump drainage? What is the operational plan during the dry weather?
I will now substantiate my initial letter. As part of the input parameters for modeling I included the length and cross section of the canals. This was not ‘by guess’. I have anticipated that the software of choice should be able to route the conservancy to the outfall, hence the need to have design information on the proposed and existing canals. The proposed canal (at Hope or Land of Canaan) should serve, at the least, dual functions: increased storage for the conservancy and act as conveyance for flood relief and is an integral part in the conservancy modeling process. I do not expect the consultant to model only the hydraulics of the canal unless (I reiterate) it is a canal design project and the flow is already known.
I did not get into details of risk analysis in my initial letter since it is not my area of expertise but what I did not expect was having engineers seek details about my risk plan specifics and suggesting that if this is rarely used as a management tool in Guyana then it should not be. My answer is simply TWW (Total Wrong Wuk). My position remains, a risk analysis study is required. The risks will eventually summarize costs and costs lead to decision making and approaches for funding. I need not be reminded about the need for dam safety analysis, this is a definite requirement.
My peers also have approximated the size of the canal needed. This I opine is premature, misleading and guesswork, even if they have access to information (reports on the conservancy) that the Government does not. Again I ask “Where are all the old reports from major projects undertaken in British Guiana”?
The Government has openly stated that Hope was the best site for the relief structure. I think they should consider making public the document/evidence that suggests that the Hope Canal is the best option before adventuring into spending $3B or are we launching the first “white” water project (as against white elephant) and I agree with Engineer Sohan that a re-tender should not be ruled out.
Yours faithfully,
Ralph Seegobin
(Professional Engineer)
2 Comments (Open | Close)
2 Comments To "Risk analysis study for conservancy relief absolutely needed"
#1 Comment By Brendan Samaroo On February 24, 2009 @ 6:13 am
Mr. President & Minister of Agriculture would it not make some sense to get all of these gentlemen together sit down and have a meeting with them and hear them out?
Is that too adult a thing for this government to consider?
#2 Comment By Cummins On February 24, 2009 @ 8:24 am
Before I took up a career in global business and policy I was a mechanical engineer. One of the things I learned and understood in undergraduate school and early career is that if engineers are arguing among themselves then nobody in the group knows what they are talking about for engineering is an (almost) exact science. All results and actions should be streaming from a UNIVERSALLY ACCEPTED mathematical formula that was TESTED and PROVEN in a laboratory setting and by prototype model. Apply the wrong formula and the results could be catastrophic and deadly. I find it disheartening that engineers are having a street fight over which formula or method to apply. In business policy we get do-overs, in engineering there are none; take it from me who have practiced in both fields.
Ralph, in the absence of knowing at what level the referenced gentlemen are in their respective careers your PE certification gives you more credibility on this argument as far as I am concerned. I am sensing the other gentlemen are more making a cost decision and we know the rule of engineering is safety first, cost second.
I wish you guys can agree on what formula should be applied.
Article printed from Stabroek News: http://www.stabroeknews.com
URL to article: http://www.stabroeknews.com/2009/letters/02/24/risk-analysis-study-for-conservancy-relief-absolutely-needed/
Sunday, February 8, 2009
The model and risk analysis are everything to the Hope Canal project
Stabroek News letter. 3 February 2009. The model and risk analysis are everything to the Hope Canal project. http://www.stabroeknews.com/letters/the-model-and-risk-analysis-are-everything-to-the-hope-canal-project-2/
Dear Editor,
I have read with interest the numerous letters and articles written about the proposed design of the relief structure(s) for the EDWC. Both engineers Malcolm Alli and Charles Sohan must be commended for their points of view. Hope bidders took advantage of those opinions. The tenders are open and it is time to evaluate.
To the designer, the hydrological model entails basins, nodes and reaches. Basins flow to nodes. Reaches (also called links) connect nodes. That translates to storing rain in a conservancy (node) and discharging it through a few structures and/or canals (reaches) to the outfalls (node). Of course, numerous software can perform this function, so what is the problem? The answer is obtaining the input parameters: determining the design storm, defining the drainage basins areas/divides, calculating the time of concentrations, calculating soil hydrologic curve numbers, computing the conservancy stage-storage relationship, determining tailwater conditions to the boundary nodes (outfall, maybe tidal), the length and cross section of canals, existing or proposed (reaches), discharge structures geometrics, head loss coefficients, other discharge coefficients, base flow characteristics (if any), evapo-transpiration losses, etc. Easy to read, but very time consuming to determine. Remember in modelling, garbage in is garbage out (the GIGO rule).
In principle the model is attenuating the rainfall (called runoff) for release at a later time, in engineering terms to control the outflow hydrograph. I would like to briefly expand on the difficulties that the designer may have to accurately determine just two of the above parameters: drainage basin areas/divides and the conservancy stage-storage relationship. Drainage basin divides give areas that define the watershed. How can these be verified? From old contour maps, maybe, or the use of areas from past reports. If we do not want to use the past records then what? Remember if less area is modelled than actually exists, the runoff will be underestimated. If there is insufficient time to verify areas then assumptions will have to be made. The conservancy stage-storage (or stage-area) relationship is required. How can this be determined? From a past report, but will this be a reflection of the existing situation? The questions can go on and on.
The bottom line is that I foresee a lot of assumptions will have to be made to run the model. A risk analysis may be required to assess the impact of the assumptions. The output of the model will therefore be used to determine the capacity of the canal. The canal and conservancy will have to be checked against some predetermined constraints and varying tailwater conditions. My point is a number of iterations and scenarios would have to be developed. Locating the canal at either Hope or Land of Canaan can be scenarios to be considered and recommended.
Are our local consultants capable of undertaking such a modelling exercise? I doubt it. It is my opinion that the GOG is skimming the surface on this one and has only a vague idea as to the depth of expertise required for this undertaking. Again I reiterate the model and risk analysis are everything to this project. Surely the local engineers can design a canal or is this what the project is all about? I also think the GOG should consider hiring Independent Technical Reviewers (ITR) to review the consultant’s work, ie model - structural, geotechnical, etc. Investing in ITR will be money well spent. My fellow engineers may have heard this before, ‘Doctors bury their mistakes, engineers live with theirs.’ I hope my view helps in some way in coming up with the best design approach.
Yours faithfully,
Ralph V Seegobin
6 Comments (Open | Close)
Dear Editor,
I have read with interest the numerous letters and articles written about the proposed design of the relief structure(s) for the EDWC. Both engineers Malcolm Alli and Charles Sohan must be commended for their points of view. Hope bidders took advantage of those opinions. The tenders are open and it is time to evaluate.
To the designer, the hydrological model entails basins, nodes and reaches. Basins flow to nodes. Reaches (also called links) connect nodes. That translates to storing rain in a conservancy (node) and discharging it through a few structures and/or canals (reaches) to the outfalls (node). Of course, numerous software can perform this function, so what is the problem? The answer is obtaining the input parameters: determining the design storm, defining the drainage basins areas/divides, calculating the time of concentrations, calculating soil hydrologic curve numbers, computing the conservancy stage-storage relationship, determining tailwater conditions to the boundary nodes (outfall, maybe tidal), the length and cross section of canals, existing or proposed (reaches), discharge structures geometrics, head loss coefficients, other discharge coefficients, base flow characteristics (if any), evapo-transpiration losses, etc. Easy to read, but very time consuming to determine. Remember in modelling, garbage in is garbage out (the GIGO rule).
In principle the model is attenuating the rainfall (called runoff) for release at a later time, in engineering terms to control the outflow hydrograph. I would like to briefly expand on the difficulties that the designer may have to accurately determine just two of the above parameters: drainage basin areas/divides and the conservancy stage-storage relationship. Drainage basin divides give areas that define the watershed. How can these be verified? From old contour maps, maybe, or the use of areas from past reports. If we do not want to use the past records then what? Remember if less area is modelled than actually exists, the runoff will be underestimated. If there is insufficient time to verify areas then assumptions will have to be made. The conservancy stage-storage (or stage-area) relationship is required. How can this be determined? From a past report, but will this be a reflection of the existing situation? The questions can go on and on.
The bottom line is that I foresee a lot of assumptions will have to be made to run the model. A risk analysis may be required to assess the impact of the assumptions. The output of the model will therefore be used to determine the capacity of the canal. The canal and conservancy will have to be checked against some predetermined constraints and varying tailwater conditions. My point is a number of iterations and scenarios would have to be developed. Locating the canal at either Hope or Land of Canaan can be scenarios to be considered and recommended.
Are our local consultants capable of undertaking such a modelling exercise? I doubt it. It is my opinion that the GOG is skimming the surface on this one and has only a vague idea as to the depth of expertise required for this undertaking. Again I reiterate the model and risk analysis are everything to this project. Surely the local engineers can design a canal or is this what the project is all about? I also think the GOG should consider hiring Independent Technical Reviewers (ITR) to review the consultant’s work, ie model - structural, geotechnical, etc. Investing in ITR will be money well spent. My fellow engineers may have heard this before, ‘Doctors bury their mistakes, engineers live with theirs.’ I hope my view helps in some way in coming up with the best design approach.
Yours faithfully,
Ralph V Seegobin
6 Comments (Open | Close)
How was the figure for the cost of the Hope Canal arrived at?
Stabroek News letter. 22 January 2009. How was the figure for the cost of the Hope Canal arrived at? http://www.stabroeknews.com/letters/how-was-the-figure-for-the-cost-of-the-hope-canal-arrived-at/
Dear Editor,
I applaud your January 12 editorial (‘Relief from the conservancy’) wherein a number of pertinent issues were raised regarding the proposed northern relief channel for the East Demerara Water Conservancy (EDWC) to be located at Hope/Dochfour.
There is no doubt this will be a complex and costly project and it is important, as was stated, that the engineering decisions be sound and carefully made to enable the completed project to satisfy the required objective of removing flood water from EDWC and discharge it into the Atlantic Ocean in an efficient, safe and timely manner.
An invitation to bid for consultancy services has been issued and responses have to be submitted by January 27. It appears there was a delay in the availability of tender documents and the time given for bid submission is evidently limited. These constraints will certainly adversely affect reputable consultants expected to submit meaningful bids let alone their ability to mobilize teams of local and foreign personnel for joint venture submissions. The National Drainage and Irrigation Authority (NDIA) should not delude itself into thinking that all the required skills needed to design and construct this project are available locally. Substantial engineering consulting work will have to be done overseas for data analyses and design since the work envisaged will include, but not be limited to flood routing and simulation/modelling of the conservancy with its various outlets to determine the capacity of the proposed relief channel. This capacity will also dictate the size and geometry of the inlet and outlet structures, channel width and slopes. Important data necessary for design remain to be collected. These will have to include stream gauging on all outlet structures to determine their discharges over a given time, but particularly during periods of heavy rainfall with the conservancy at its optimum level. Geotechnical investigations will have to be carried out for the foundations of the many structures to be built as well as for the channel slope and embankments. The effects of sling mud and other littoral drifts as well as tidal fluctuations on the discharge of the outlet structure into the ocean to ensure optimum output at all times will have to be determined for the purposes of hydraulic design. Last but not least will be the need for comprehensive topographic and detailed site surveys for various aspects of the project design. The consultants should also be required to examine the feasibility of constructing one outlet structure, preferably across the sea defence for the release of floodwater from the conservancy directly into the ocean instead of two (the other across the conservancy dam) as is now contemplated. This could possibly result in considerable project cost reduction.
After all the relevant data have been collected and analyzed, and the design completed, tenders will have to be invited for project construction unless NDIA is contemplating a turnkey project. If a construction contract is contemplated, it will take several months for contract review and award as well as for the contractor’s mobilization before actual construction starts. Therefore given the size and complexity of this project it is unlikely that it could be completed and functional in under three years.
Based on the requirements for data collection, design and construction given above it is inconceivable that this project could start in June ’09 and be completed by June ’10. Another major hurdle yet to overcome is funding. A cost of $3 billion (US$15 million) for this project has been stated by the President of the Republic. It is mind boggling as to how this figure was arrived at, since no design, bill of quantities and costing have been prepared for this project. NDIA has to assure the people of Region 4 in no uncertain terms where funding to construct this project will come from, particularly during this difficult financial period when loans, gifts and handouts have all but disappeared. In addition, the government has incurred large external debts, and is strapped for cash to carry out even basic services or provide financial assistance to flood-stricken farmers in the region and elsewhere who have suffered damage to their homes, loss of livestock and crops and who are on the verge of starvation as a result of the yearly flooding of their homesteads due to mismanagement and the lack of adequate investment in the drainage system in their community.
Finally, the residents of Region 4 should not be misled into thinking that the proposed relief channel for the EDWC will be constructed any time soon, despite the rhetoric. NDIA is accustomed to crisis management of its facilities, and much of the same should be expected during those cycles of heavy rainfall yet to come. Nevertheless, this is an important project and if it does get off the ground its execution should be transparent. Its design and construction should be undertaken by reputable consultants/contractors with proven track records to ensure that public funds are well spent on a much needed project whose objective is to alleviate the yearly sufferings and fears caused by flooding. It is hoped this project does not end up being another Amaila Falls Hydropower or Marriott Hotel, projects which have gone nowhere despite high expectations and the injudicious doling out of scarce tax dollars to undertake questionable upfront preliminary works hurriedly thought-out and based on uncertain promises.
Yours faithfully,
Charles Sohan
9 Comments (Open | Close)
Dear Editor,
I applaud your January 12 editorial (‘Relief from the conservancy’) wherein a number of pertinent issues were raised regarding the proposed northern relief channel for the East Demerara Water Conservancy (EDWC) to be located at Hope/Dochfour.
There is no doubt this will be a complex and costly project and it is important, as was stated, that the engineering decisions be sound and carefully made to enable the completed project to satisfy the required objective of removing flood water from EDWC and discharge it into the Atlantic Ocean in an efficient, safe and timely manner.
An invitation to bid for consultancy services has been issued and responses have to be submitted by January 27. It appears there was a delay in the availability of tender documents and the time given for bid submission is evidently limited. These constraints will certainly adversely affect reputable consultants expected to submit meaningful bids let alone their ability to mobilize teams of local and foreign personnel for joint venture submissions. The National Drainage and Irrigation Authority (NDIA) should not delude itself into thinking that all the required skills needed to design and construct this project are available locally. Substantial engineering consulting work will have to be done overseas for data analyses and design since the work envisaged will include, but not be limited to flood routing and simulation/modelling of the conservancy with its various outlets to determine the capacity of the proposed relief channel. This capacity will also dictate the size and geometry of the inlet and outlet structures, channel width and slopes. Important data necessary for design remain to be collected. These will have to include stream gauging on all outlet structures to determine their discharges over a given time, but particularly during periods of heavy rainfall with the conservancy at its optimum level. Geotechnical investigations will have to be carried out for the foundations of the many structures to be built as well as for the channel slope and embankments. The effects of sling mud and other littoral drifts as well as tidal fluctuations on the discharge of the outlet structure into the ocean to ensure optimum output at all times will have to be determined for the purposes of hydraulic design. Last but not least will be the need for comprehensive topographic and detailed site surveys for various aspects of the project design. The consultants should also be required to examine the feasibility of constructing one outlet structure, preferably across the sea defence for the release of floodwater from the conservancy directly into the ocean instead of two (the other across the conservancy dam) as is now contemplated. This could possibly result in considerable project cost reduction.
After all the relevant data have been collected and analyzed, and the design completed, tenders will have to be invited for project construction unless NDIA is contemplating a turnkey project. If a construction contract is contemplated, it will take several months for contract review and award as well as for the contractor’s mobilization before actual construction starts. Therefore given the size and complexity of this project it is unlikely that it could be completed and functional in under three years.
Based on the requirements for data collection, design and construction given above it is inconceivable that this project could start in June ’09 and be completed by June ’10. Another major hurdle yet to overcome is funding. A cost of $3 billion (US$15 million) for this project has been stated by the President of the Republic. It is mind boggling as to how this figure was arrived at, since no design, bill of quantities and costing have been prepared for this project. NDIA has to assure the people of Region 4 in no uncertain terms where funding to construct this project will come from, particularly during this difficult financial period when loans, gifts and handouts have all but disappeared. In addition, the government has incurred large external debts, and is strapped for cash to carry out even basic services or provide financial assistance to flood-stricken farmers in the region and elsewhere who have suffered damage to their homes, loss of livestock and crops and who are on the verge of starvation as a result of the yearly flooding of their homesteads due to mismanagement and the lack of adequate investment in the drainage system in their community.
Finally, the residents of Region 4 should not be misled into thinking that the proposed relief channel for the EDWC will be constructed any time soon, despite the rhetoric. NDIA is accustomed to crisis management of its facilities, and much of the same should be expected during those cycles of heavy rainfall yet to come. Nevertheless, this is an important project and if it does get off the ground its execution should be transparent. Its design and construction should be undertaken by reputable consultants/contractors with proven track records to ensure that public funds are well spent on a much needed project whose objective is to alleviate the yearly sufferings and fears caused by flooding. It is hoped this project does not end up being another Amaila Falls Hydropower or Marriott Hotel, projects which have gone nowhere despite high expectations and the injudicious doling out of scarce tax dollars to undertake questionable upfront preliminary works hurriedly thought-out and based on uncertain promises.
Yours faithfully,
Charles Sohan
9 Comments (Open | Close)
Jagdeo in talks for donor funding for proposed $3B Hope canal.
Stabroek News news item. 20 January 2009. Jagdeo in talks for donor funding for proposed $3B Hope canal. http://www.stabroeknews.com/news/jagdeo-in-talks-for-donor-funding-for-proposed-3b-hope-canal/
President Bharrat Jagdeo said he is in discussion with donors to fund the $3B Hope Conservancy Relief project, but was against releasing any names yesterday since it is still early in the negotiations.
Though expenditure for the project will be reflected in this year’s budget, he disclosed that he is in talks to secure part funding. The President was at the time addressing the media at a press conference at State House.
The Head of State pointed out that the $100M that allocated to affect farmers in areas which have been severely affected by flooding is currently being disbursed and according to him the assistance is not the end of it. He declared that the administration will continue to “hold [farmers] hands throughout the whole process”.
In emphasizing the point about continued assistance being shown to those affected, Jagdeo said, a plan has already been drawn up for the full amount of allocated resources to be used up. He said some $16M had been handed out up to yesterday.
The President pointed out that some of the assistance to farmers would include the distribution of seeds; chemical; fertilizer; veterinary supplies; livestock feed; spraying equipment and fuel among other items, which are part of the plan that have been worked out.
It is expected that will work on the Hope Conservancy Relief project, which will constantly drain water from the East Demerara Water Conservancy (EDWC) into the Atlantic Ocean can begin within six months. Jagdeo has previously insisted that this initiative is being treated as a priority and that certain projects such as the construction of roads will be held back so as to ensure that the project is completed by June 2010.
Currently, water, when it is near the top of the conservancy which can hold 59 GD, is drained through the Mahaica Creek, which affects thousands of residents in the area. About three weeks ago, water from the EDWC was released through the Maduni and later the Lama sluices which added to the rain water which had already accumulated on the land.
President Bharrat Jagdeo said he is in discussion with donors to fund the $3B Hope Conservancy Relief project, but was against releasing any names yesterday since it is still early in the negotiations.
Though expenditure for the project will be reflected in this year’s budget, he disclosed that he is in talks to secure part funding. The President was at the time addressing the media at a press conference at State House.
The Head of State pointed out that the $100M that allocated to affect farmers in areas which have been severely affected by flooding is currently being disbursed and according to him the assistance is not the end of it. He declared that the administration will continue to “hold [farmers] hands throughout the whole process”.
In emphasizing the point about continued assistance being shown to those affected, Jagdeo said, a plan has already been drawn up for the full amount of allocated resources to be used up. He said some $16M had been handed out up to yesterday.
The President pointed out that some of the assistance to farmers would include the distribution of seeds; chemical; fertilizer; veterinary supplies; livestock feed; spraying equipment and fuel among other items, which are part of the plan that have been worked out.
It is expected that will work on the Hope Conservancy Relief project, which will constantly drain water from the East Demerara Water Conservancy (EDWC) into the Atlantic Ocean can begin within six months. Jagdeo has previously insisted that this initiative is being treated as a priority and that certain projects such as the construction of roads will be held back so as to ensure that the project is completed by June 2010.
Currently, water, when it is near the top of the conservancy which can hold 59 GD, is drained through the Mahaica Creek, which affects thousands of residents in the area. About three weeks ago, water from the EDWC was released through the Maduni and later the Lama sluices which added to the rain water which had already accumulated on the land.
Two consultancies bid for Hope canal
Stabroek News news item. 28 January 2009. Two consultancies bid for Hope canal. http://www.stabroeknews.com/news/two-consultancies-bid-for-hope-canal/
Two bids have been submitted to the National Procurement and Tender Administration Board, for consultancy services for the construction of the Hope Conservancy Relief Structure.
One of the bids was submitted by E&A Consultants Inc. and the other was a joint bid submitted by the SRK Engineering firm in association with McDonald’s Construction Company. Stabroek News has confirmed that E&A Consultants Inc. and SRK Engineering are local firms.
The tenders were yesterday opened in the boardroom of the National Procurement and Tender Administration Board of the Ministry of Finance, after the deadline was extended by one week. Minister of Agriculture Robert Persaud told Stabroek News last week that this was done to facilitate bids from interested overseas-based engineers.
The firms have tendered to provide consultancy services for the provision of engineering design of the East Demerara Water Conservancy Northern Relief Structure at Hope/Dochfour, East Coast Demerara, Region No.4. Recently, President Bharrat Jagdeo announced that $3B was being budgeted for the building of a special relief channel to drain water from the East Demerara Water Conservancy (EDWC). After a period of consultancy, work on the relief channel is expected to begin later this year and is slated to be completed by June 2010.
Stabroek News was told yesterday that the bids will be subjected to the normal procedure regarding such projects. This means that they will be examined by an evaluation team-which will most likely comprise a senior official of the National Drainage and Irrigation Authority (NDIA) and experienced engineers. The bids will be examined according to the criteria within the bid document and once all the necessary criteria are met a recommendation will be made. This recommendation will then have to be confirmed by the National Procurement and Tender Administration Board of the Ministry of Finance. This process could be completed within a month this newspaper was told.
However, there are mixed views about the construction of this conservancy with several experienced engineers saying that such a construction may not be the best option to drain the EDWC. Minister of Agriculture Robert Persaud, however, said that the exact form of this relief channel has not been confirmed as yet and that the best engineering decision will be made.
Another major concern raised was whether the one year deadline set by the government is realistic, especially when factors such as the size and complexity of the project are considered. One letter writer, Charles Sohan, opined that a project of such magnitude would take a minimum of three years to be completed.
Sohan also queried how the figure of $3B (US$15M) was arrived at since no design, bill of quantities and costing have been prepared for this project. Experienced local engineer, Malcolm Alli also stated that $3B will not be enough to complete the job. He said that the extensive construction which would include constructing a canal 80 ft wide and 10 miles long, as well as two large sluices, several bridges over the canal, a bridge at the roadway, access roads and other structures will all have to be financed.
Alli advised that rather than investing in this relief structure, that efforts be made to improve the 5-door sluice at Land of Canaan on the East Bank of Demerara in addition to the one 7-door Abary Control Sluice at the Abary River.
Project Director of the Guyana Citizen’s Initiative (GCI), Dr Rupert Roopnaraine told Stabroek News that the authorities should work on improving the outlets towards the Demerara River rather than invest so much money in what is a challenging undertaking. According to Roopnaraine, he has been advised by engineers that improving the capacity of the outlets closer to the Demerara River would greatly ease the strain on the side of the EDWC nearer to the Atlantic Ocean.
Meanwhile Executive member of the Guyana Association of Professional Engineers (GAPE), Melvyn Sankies stated that it is imperative that advice from older engineers be sought. Minister Robert Persaud said that the government is open to advice from such individuals.
This newspaper was reliably informed that the authorities have approached a senior local engineer for advice on the way forward concerning this relief channel.
Two bids have been submitted to the National Procurement and Tender Administration Board, for consultancy services for the construction of the Hope Conservancy Relief Structure.
One of the bids was submitted by E&A Consultants Inc. and the other was a joint bid submitted by the SRK Engineering firm in association with McDonald’s Construction Company. Stabroek News has confirmed that E&A Consultants Inc. and SRK Engineering are local firms.
The tenders were yesterday opened in the boardroom of the National Procurement and Tender Administration Board of the Ministry of Finance, after the deadline was extended by one week. Minister of Agriculture Robert Persaud told Stabroek News last week that this was done to facilitate bids from interested overseas-based engineers.
The firms have tendered to provide consultancy services for the provision of engineering design of the East Demerara Water Conservancy Northern Relief Structure at Hope/Dochfour, East Coast Demerara, Region No.4. Recently, President Bharrat Jagdeo announced that $3B was being budgeted for the building of a special relief channel to drain water from the East Demerara Water Conservancy (EDWC). After a period of consultancy, work on the relief channel is expected to begin later this year and is slated to be completed by June 2010.
Stabroek News was told yesterday that the bids will be subjected to the normal procedure regarding such projects. This means that they will be examined by an evaluation team-which will most likely comprise a senior official of the National Drainage and Irrigation Authority (NDIA) and experienced engineers. The bids will be examined according to the criteria within the bid document and once all the necessary criteria are met a recommendation will be made. This recommendation will then have to be confirmed by the National Procurement and Tender Administration Board of the Ministry of Finance. This process could be completed within a month this newspaper was told.
However, there are mixed views about the construction of this conservancy with several experienced engineers saying that such a construction may not be the best option to drain the EDWC. Minister of Agriculture Robert Persaud, however, said that the exact form of this relief channel has not been confirmed as yet and that the best engineering decision will be made.
Another major concern raised was whether the one year deadline set by the government is realistic, especially when factors such as the size and complexity of the project are considered. One letter writer, Charles Sohan, opined that a project of such magnitude would take a minimum of three years to be completed.
Sohan also queried how the figure of $3B (US$15M) was arrived at since no design, bill of quantities and costing have been prepared for this project. Experienced local engineer, Malcolm Alli also stated that $3B will not be enough to complete the job. He said that the extensive construction which would include constructing a canal 80 ft wide and 10 miles long, as well as two large sluices, several bridges over the canal, a bridge at the roadway, access roads and other structures will all have to be financed.
Alli advised that rather than investing in this relief structure, that efforts be made to improve the 5-door sluice at Land of Canaan on the East Bank of Demerara in addition to the one 7-door Abary Control Sluice at the Abary River.
Project Director of the Guyana Citizen’s Initiative (GCI), Dr Rupert Roopnaraine told Stabroek News that the authorities should work on improving the outlets towards the Demerara River rather than invest so much money in what is a challenging undertaking. According to Roopnaraine, he has been advised by engineers that improving the capacity of the outlets closer to the Demerara River would greatly ease the strain on the side of the EDWC nearer to the Atlantic Ocean.
Meanwhile Executive member of the Guyana Association of Professional Engineers (GAPE), Melvyn Sankies stated that it is imperative that advice from older engineers be sought. Minister Robert Persaud said that the government is open to advice from such individuals.
This newspaper was reliably informed that the authorities have approached a senior local engineer for advice on the way forward concerning this relief channel.
Agri Minister says best engineering decision will be made
Stabroek News news item, 26 January 2009. Wisdom of Hope canal queried. http://www.stabroeknews.com/news/wisdom-of-hope-canal-queried/
Agri Minister says best engineering decision will be made
Government’s decision to construct a canal at Hope to drain the East Demerara Water Conservancy (EDWC) into the Atlantic Ocean has come in for scrutiny and at least one experienced engineer, Malcolm Alli, has publicly declared that the proposed construction is not the best option.
Robert Persaud
Robert Persaud
President Bharrat Jagdeo recently announced that his government will spend $3B towards the construction of this East Coast canal which is expected to serve as a more efficient and less destructive means of releasing water from the conservancy. At present, when the EDWC is at a dangerous level, water from the conservancy is drained through the Maduni and Lama sluices. The water then flows into the Mahaica creek. This has caused catastrophic flooding in the Mahaica and Mahaicony areas in three of the last four years.
In an attempt to counteract this problem, the government is proposing that a relief channel be constructed from the EDWC to the Atlantic Ocean through the Hope/ Dochfour area on the East Coast of Demerara. This is an option that had been recommended since the Great Flood in 2005.
However, recently several persons, including engineers and farmers, have been questioning the wisdom of such a canal, arguing that there were better and cheaper ways of solving the problem.
When these points were raised with Minister of Agriculture Robert Persaud, he told this newspaper that the exact structure of this relief channel has not been confirmed as yet and that the best engineering decision will be made concerning this outlet. Persaud said that his ministry will not be dismissive of any ideas coming from experienced engineers but emphasized that the best technical decision will be made. He said that the project has gone out for tender and consequently this means that it has been opened to all those persons who feel that they have something worthwhile to contribute.
When Stabroek News contacted President of the Guyana Association of Professional Engineers (GAPE), Melvin Sankies for comment, he said that it is imperative that advice from older engineers be sought. Sankies said that the older engineers have both knowledge and experience and consequently can be useful to the younger engineers who may be tasked with the project.
Meanwhile, this newspaper was reliably informed that an experienced local engineer has been tasked by the government to review the proposals on the project and to advise accordingly.
In a letter published in the January 13 edition of the Stabroek News, engineer Malcolm Alli argued that the proposed canal was not the best option to drain the conservancy. Alli played a significant role in the MMA scheme as well as designed and supervised the construction of the 7-door Abary Control Sluice, and has many years of experience as an engineer. According to him, extensive studies carried out by the Hydraulics Division during the 1960s determined that the Land of Canaan (LOC) sluice on the East Bank was the best location and option to drain the conservancy.
The studies by the Hydraulics Division determined that an Atlantic relief would likely be subject to some tidal lock which would be undesirable for a spillway operation. According to Alli, the discharge sluice at the sea wall end could only work on a tidal basis six hours a day discharging a small amount of water daily.
The sluice at Land of Canaan is a 5-door high sill sluice that was built in the 1960s. And according to Alli, it was built specifically to drain the EDWC. He explained that the sluice can discharge 2000 cusecs of water when working on a 24-hour basis, independent of the tide.
Alli, however, asserted that the sluice at Land of Canaan is not working as it should and that specific work should be done to improve its capacity. This, he said, would be a cheaper way of solving the problem that the authorities had in dealing with draining the conservancy.
Outlets
Similar thoughts were echoed by Project Director of the Guyana Citizen’s Initiative (GCI), Dr Rupert Roopnaraine. When contacted by Stabroek News, Roopnaraine said that the authorities may be better advised to at least consider improving the outlets towards the Demerara River rather than investing so much money in what is clearly a very challenging undertaking. Previously, the GCI had called for the rehabilitation of the Cunha canal and outfall to aid in the conservancy’s drainage. And according to Roopnaraine, it would not hurt for the authorities to at least look at improving the sluice at Land of Canaan. He said that based on engineering advice he has received, releasing water from this end of the conservancy would greatly ease the strain on the side of the EDWC nearer to the Atlantic Ocean.
When Minister Persaud was asked about the Land of Canaan sluice, he said that the “jury was out as to whether the capacity of this sluice could be improved”. While saying that there were no immediate plans to work on this sluice, he did not rule out work being done in the future. He once more confirmed that efforts were being concentrated on the resuscitating of the Cunha outlet to the Demerara River, which he said was only operating at about 40% of its capacity and which obviously could be improved.
Persaud said the peculiar situation with the conservancy is that the water levels stored towards the Atlantic end of the conservancy were higher than the levels at the Demerara River end. Consequently, that was why work on the relief channel that drains into the Atlantic Ocean was being implemented. Observers say such a phenomenon might indicate blocked internal drainage channels or greater sedimentation in the northern section of the conservancy.
Meanwhile, Alli also said that the failure to maintain the 7-door Abary Control Sluice was another cause of the problems with draining the conservancy.
He said that a certain amount of water had to be released from the sluice daily so as to keep the Abary River alive, but this was never done. According to Alli due to the failure of water to be released, the Abary has become silted for about 45 miles. He also said that he does not believe that the sluice was functioning.
Technical advice
When the Agriculture Minister was asked about this sluice, he said that he had been advised by the MMA authorities that this sluice can be operational and can release water from the conservancy into the Abary creek. He said that he was told that during the low-tide that the sluice is opened.
The minister, however, hinted that this sluice is not working as it should and explained that he is waiting on the technical staff of the MMA to provide him with some more “technical advice” on the state of this sluice.
One farmer from the Abary area, in a letter published in this newspaper, said that the sluice has not been working for more than twelve years. Persaud, however, stated that he was not in a position to confirm or dispute whether the sluice has not been properly functioning for such a lengthy period.
Meantime, Alli also opined that the conservancy has not been properly maintained, and consequently this has resulted in it reaching a critical stage of siltation and vegetation inhibiting its storage capacity.
During a recent tour of the EDWC by media personnel, Secretary of the EDWC Board, Stephen La Fleur said that over the years several of the conservancy channels had been blocked up by vegetation and silt and that work had been and continues to be done to clear some of these channels.
Alli also argued that to facilitate this new relief channel may cost more than the $3B budgeted since considering the magnitude of the project. According to him, the proposed works for the relief channel will be extensive since the canal has to be a high level canal with some 80 ft bed width and about 10 miles long.
Further, it would require the construction of two large sluices in addition to several bridges over the canal, a bridge at the roadway, access roads and more.
President Jagdeo has announced that money has already been budgeted to get the project started by June/July but said that he is currently in negotiations to secure part funding for the project. If all goes according to plan, the proposed date for the completion of the channel is June 2010.
However, another letter writer Charles Sohan suggested that the proposed deadline was overly ambitious, especially when the amount of work required is considered. In his letter, he said that “based on the requirements for data collection, design and construction…it is inconceivable that this project could start in June 2009 and be completed by June 2010. He added that “given the size and complexity of this project (the Hope Relief Channel) it is unlikely that it could be completed and functional in under three years”.
Sohan also questioned how the sum of $3B (US$15M) that has been budgeted was determined. He said that “it was mind boggling as to how this figure was arrived at, since no design, bill of quantities and costing have been prepared for this project.”
Agri Minister says best engineering decision will be made
Government’s decision to construct a canal at Hope to drain the East Demerara Water Conservancy (EDWC) into the Atlantic Ocean has come in for scrutiny and at least one experienced engineer, Malcolm Alli, has publicly declared that the proposed construction is not the best option.
Robert Persaud
Robert Persaud
President Bharrat Jagdeo recently announced that his government will spend $3B towards the construction of this East Coast canal which is expected to serve as a more efficient and less destructive means of releasing water from the conservancy. At present, when the EDWC is at a dangerous level, water from the conservancy is drained through the Maduni and Lama sluices. The water then flows into the Mahaica creek. This has caused catastrophic flooding in the Mahaica and Mahaicony areas in three of the last four years.
In an attempt to counteract this problem, the government is proposing that a relief channel be constructed from the EDWC to the Atlantic Ocean through the Hope/ Dochfour area on the East Coast of Demerara. This is an option that had been recommended since the Great Flood in 2005.
However, recently several persons, including engineers and farmers, have been questioning the wisdom of such a canal, arguing that there were better and cheaper ways of solving the problem.
When these points were raised with Minister of Agriculture Robert Persaud, he told this newspaper that the exact structure of this relief channel has not been confirmed as yet and that the best engineering decision will be made concerning this outlet. Persaud said that his ministry will not be dismissive of any ideas coming from experienced engineers but emphasized that the best technical decision will be made. He said that the project has gone out for tender and consequently this means that it has been opened to all those persons who feel that they have something worthwhile to contribute.
When Stabroek News contacted President of the Guyana Association of Professional Engineers (GAPE), Melvin Sankies for comment, he said that it is imperative that advice from older engineers be sought. Sankies said that the older engineers have both knowledge and experience and consequently can be useful to the younger engineers who may be tasked with the project.
Meanwhile, this newspaper was reliably informed that an experienced local engineer has been tasked by the government to review the proposals on the project and to advise accordingly.
In a letter published in the January 13 edition of the Stabroek News, engineer Malcolm Alli argued that the proposed canal was not the best option to drain the conservancy. Alli played a significant role in the MMA scheme as well as designed and supervised the construction of the 7-door Abary Control Sluice, and has many years of experience as an engineer. According to him, extensive studies carried out by the Hydraulics Division during the 1960s determined that the Land of Canaan (LOC) sluice on the East Bank was the best location and option to drain the conservancy.
The studies by the Hydraulics Division determined that an Atlantic relief would likely be subject to some tidal lock which would be undesirable for a spillway operation. According to Alli, the discharge sluice at the sea wall end could only work on a tidal basis six hours a day discharging a small amount of water daily.
The sluice at Land of Canaan is a 5-door high sill sluice that was built in the 1960s. And according to Alli, it was built specifically to drain the EDWC. He explained that the sluice can discharge 2000 cusecs of water when working on a 24-hour basis, independent of the tide.
Alli, however, asserted that the sluice at Land of Canaan is not working as it should and that specific work should be done to improve its capacity. This, he said, would be a cheaper way of solving the problem that the authorities had in dealing with draining the conservancy.
Outlets
Similar thoughts were echoed by Project Director of the Guyana Citizen’s Initiative (GCI), Dr Rupert Roopnaraine. When contacted by Stabroek News, Roopnaraine said that the authorities may be better advised to at least consider improving the outlets towards the Demerara River rather than investing so much money in what is clearly a very challenging undertaking. Previously, the GCI had called for the rehabilitation of the Cunha canal and outfall to aid in the conservancy’s drainage. And according to Roopnaraine, it would not hurt for the authorities to at least look at improving the sluice at Land of Canaan. He said that based on engineering advice he has received, releasing water from this end of the conservancy would greatly ease the strain on the side of the EDWC nearer to the Atlantic Ocean.
When Minister Persaud was asked about the Land of Canaan sluice, he said that the “jury was out as to whether the capacity of this sluice could be improved”. While saying that there were no immediate plans to work on this sluice, he did not rule out work being done in the future. He once more confirmed that efforts were being concentrated on the resuscitating of the Cunha outlet to the Demerara River, which he said was only operating at about 40% of its capacity and which obviously could be improved.
Persaud said the peculiar situation with the conservancy is that the water levels stored towards the Atlantic end of the conservancy were higher than the levels at the Demerara River end. Consequently, that was why work on the relief channel that drains into the Atlantic Ocean was being implemented. Observers say such a phenomenon might indicate blocked internal drainage channels or greater sedimentation in the northern section of the conservancy.
Meanwhile, Alli also said that the failure to maintain the 7-door Abary Control Sluice was another cause of the problems with draining the conservancy.
He said that a certain amount of water had to be released from the sluice daily so as to keep the Abary River alive, but this was never done. According to Alli due to the failure of water to be released, the Abary has become silted for about 45 miles. He also said that he does not believe that the sluice was functioning.
Technical advice
When the Agriculture Minister was asked about this sluice, he said that he had been advised by the MMA authorities that this sluice can be operational and can release water from the conservancy into the Abary creek. He said that he was told that during the low-tide that the sluice is opened.
The minister, however, hinted that this sluice is not working as it should and explained that he is waiting on the technical staff of the MMA to provide him with some more “technical advice” on the state of this sluice.
One farmer from the Abary area, in a letter published in this newspaper, said that the sluice has not been working for more than twelve years. Persaud, however, stated that he was not in a position to confirm or dispute whether the sluice has not been properly functioning for such a lengthy period.
Meantime, Alli also opined that the conservancy has not been properly maintained, and consequently this has resulted in it reaching a critical stage of siltation and vegetation inhibiting its storage capacity.
During a recent tour of the EDWC by media personnel, Secretary of the EDWC Board, Stephen La Fleur said that over the years several of the conservancy channels had been blocked up by vegetation and silt and that work had been and continues to be done to clear some of these channels.
Alli also argued that to facilitate this new relief channel may cost more than the $3B budgeted since considering the magnitude of the project. According to him, the proposed works for the relief channel will be extensive since the canal has to be a high level canal with some 80 ft bed width and about 10 miles long.
Further, it would require the construction of two large sluices in addition to several bridges over the canal, a bridge at the roadway, access roads and more.
President Jagdeo has announced that money has already been budgeted to get the project started by June/July but said that he is currently in negotiations to secure part funding for the project. If all goes according to plan, the proposed date for the completion of the channel is June 2010.
However, another letter writer Charles Sohan suggested that the proposed deadline was overly ambitious, especially when the amount of work required is considered. In his letter, he said that “based on the requirements for data collection, design and construction…it is inconceivable that this project could start in June 2009 and be completed by June 2010. He added that “given the size and complexity of this project (the Hope Relief Channel) it is unlikely that it could be completed and functional in under three years”.
Sohan also questioned how the sum of $3B (US$15M) that has been budgeted was determined. He said that “it was mind boggling as to how this figure was arrived at, since no design, bill of quantities and costing have been prepared for this project.”
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