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)
