Of the Maduni, Lama, Kofi and Cunha sluices and the spill weir at Land of Canaan which drain the East Demerara Water Conser-vancy (EDWC), only the ones at Maduni and Lama are currently functioning at their full capacity, Agriculture Minister Robert Persaud told the National Assembly on Thursday.
Responding in writing to questions posed by PNCR-1G Chief Whip Lance Carberry, Persaud said the sluices at Kofi and Cunha in addition to the spill weir are currently not functioning at their “original design capacity for reasons of cross conservancy hydraulic gradients”. According to Persaud, while the Cunha sluice has an operating capacity of 55.0 m3/sec it is currently operating at 35.0-40.0 m3/sec (1235-1415 cfs). He also said that the spill weir at Land of Canaan is currently functioning at 40.0-45 m3/ sec (1415-1590 cfs) when it has a capacity of 56.6m3/sec or 2000 cfs at a water level of 57.5 GD. The minister said too that that the Kofi sluice was functioning at a rate of 55.0-60.0 m3/ sec (1940-2120cfs) but did not state its capacity operation level. Further, Persaud stated that the Maduni Sluice and the Lama Canals were functioning at their maximum capacities of 55.0m3/ sec.
Regarding the EDWC, the minister told the House that at the level of 58.80 GD, there is a threat that the dam of the conservancy would overtop. Persaud disclosed too that every year since January 2005, the water level exceeded the 58.50 GD at Flagstaff, which is regarded as the “minimum safe level”.
Meanwhile, Persaud responded to questions raised by Carberry regarding the proposed Hope Relief Channel and once again emphasised that the selected option was done based on sound technical advice. He said too that “a feasibility study would stand only to re-confirm the deficiencies in the flood relief capacity of the EDWC” that were known for 60 years and confirmed by recent floods.
According to the minister, previous studies had recommended an additional outlet to address the drainage problems of the conservancy, which is 60 km long with a catchment area of 582 km. He identified the studies conducted under UNDAC 2005 and the Conservancy Flood Manage-ment Modelling Report 2005 as the two studies conducted. He also pointed to the Infrastructure Rehabilitation Plan prepared by Mott MacDonald in 2005, which recommended an additional 30-metre wide flood relief structure “to pass a 10,000-year flood” to improve the safety standards of the conservancy. Persaud also pointed to the hydrological and reservoir studies undertaken by CEMCO/ SRKN’gineering in association with Mott Mac Donald which determined that “the conservancy does not act as a level pool with observed cross conservancy hydraulic gradient often of the order 2ft to 3 ft”.
Persaud informed the National Assembly that while the consultants had recommended the weir discharge they had also considered a deep foreshore discharge and a relief channel from Flagstaff to the Mahaica River.
The minister also said that an Environmental Manage-ment Plan (EMP) was submitted to the National Drainage and Irrigation Authority by the consultancy firm. The EMP was produced by the sub consultant, Environmental Management Consultants (EMC), the minister said too.
