Dear Editor,
In a SN article of May 27, the Agriculture Minister stated that the design to upgrade the drainage capacity of the Cunha sluice/canal on the East Bank Demerara has been completed and the documents are to be transmitted to the World Bank for funding, the cost of which is estimated at US$I.5M.
In year 2008 under Grant No. TF 058177 from the World Bank to the Govern-ment of Guyana (GoG), proposals inviting pre-investment studies for engineering works and supervision of specific Conservancy Adaptation Works (CAP) were made available and interested consultants were pre-qualified and invited to submit bids for the project. The expected date for commencement of consulting services was January 2009, but to date no award has been made and the project appears to be at a standstill. Under CAP terms of reference, the Cunha relief outlet as a project sub-task would require engineering analysis and design to substantially increase its relief capacity, including canal realignment, highway bridge construction and sluice modifications. It was expected that the consultants would maximize the design capacity of the expanded structure consistent with site conditions and local/regional land use constraints. It seems, however, that the Ministry of Agricul-ture (MoA) has decided to ‘cherry-pick’ elements of the proposed project and list them as priority for implementation with or without funding from the World Bank, with Cunha being one of these.
The key challenge facing coastal Guyana is management of its poor drainage infrastructure for flood control. There is no comprehensive analysis for a coastal flood management system, and more fundamentally the country lacks a functional topographic baseline for drainage analysis. Hence, at present flood control is managed on an emergency basis, and control efforts are focused on responding to emergency needs with a drainage pump here and a drainage pump there to soothe angry constituents, rather than the development of long-term flood control strategies.
The CAP was intended to fill this gap, and it would have given the MoA a blueprint to reduce the country’s vulnerability to catastrophic flooding through methods designed to increase the drainage relief capacity of the East Demerara Water Conservancy (EDWC), and give the National Drainage and Irrigation Authority (NDIA) a clearer and better understanding of the EDWC system and in general coastal land drainage regimes.
Without a clear understanding of the factors which impact drainage regimes, the MoA/NDIA cannot effectively manage conservancy water levels during periods of intense rainfall, nor specifically increase the drainage relief capacity of EDWC since it lacks the knowledge to improve the Cunha sluice/canal and other relief structures discharge characteristics and means of changing the internal flow dynamics of the EDWC system to allow for greater flows to the Demerara River.
The Land of Canaan sluice was designed to discharge from the EDWC 2000 cubic feet per second (cfs) at optimum capacity, but recent flow measurements indicate that it is discharging less than 800 cfs, and the MoA has been unable to ascertain the cause for this deficiency and/or what action should be taken to improve its performance. It is inconceivable therefore that improving the drainage capacity of the Cunha sluice per se could be achieved without improvements to ancillary works, such as increased conveyance of floodwater flows east to west through enlarged internal cross canals to provide the necessary conveyance for optimum discharge.
The MoA should pursue implementation of CAP, and based on the recommendations therein a set of works including the Cunha sluice/canal could then be developed for approval and execution to effectively, safely and efficiently relieve flood waters from the EDWC, since it is unlikely that the World Bank and other donor agencies will fund a disjointed project that is not carefully planned, designed and integrated with the whole, and when executed fail to substantially reduce the country’s vulnerability to catastrophic flooding.
Yours faithfully,
Charles Sohan
