GUY-14: Dead or alive: Damming has raised serious questions about Abary River
Christopher Yaw Stabroek News, Georgetown, Region 4 mayo 2006
While the Abary River came to prominence this year during the unprecedented inundation in the area, questions are being asked about whether the river is dead - or at least if its characteristics have been radically changed by its damming - and if this has impacted on riverain habitat and compounds flooding.
The river was pinpointed as one of the major factors in the slow run-off of water from the affected Region Five areas, in particular the Mahaica/Mahaicony/Abary-Agricultural Development Authority (MMA/ADA) area during the flood of December/January 2005/06.
It is one of three waterways in the region, but is distinct from the others, the Mahaica and Mahaicony Rivers, in the sense that since 1983 it was dammed to create the Abary Conservancy. It may be described as a large natural stream of water flowing 35 miles from the seven-door sluice at Copeman, West Coast Berbice, under the Rosignol Public Road to the Abary Sluice.
Chairman of the MMA/ADA Rudolph Gajraj in a letter to the press earlier this year gave some background on the genesis of the Abary River Control Project. He stated that the MMA project had its beginnings since 1952. At that time, F.H. Hutchinson, then consulting engineer to the Government laid out his ideas for water control in the Mahaicony and Abary catchments. In 1953, those ideas were expanded on by Lacey, then adviser to the Government, to include the Mahaica. In the mid-1950s work commenced with surveys and data gathering. By 1961 the project report with the detailed designs and cost estimates for Stage 1 - Control of the Abary - were completed by the Government Drainage and Irrigation Department. Robert Camacho a civil engineer and Halcrow's Resident Representative in Guyana and Project Director for the Abary River Water Control Project from 1978 to 1980 was then director of the department, and the report and designs acknowledged the work of the consulting engineers Drury and Rowe, as well as the many surveyors, draughtsmen and other local staff of the department. By 1978 when the first IDB loan was finalized, a re-appraisal of the 1961 work had been undertaken and completed between 1975 and 1976, by international consultants Halcrow and Partners. Many of the re-appraisal studies benefited from new technologies that had been developed by then. (The Abary River tidal drainage studies, which included a mathematical model of the Abary River was one to so benefit.) In the end, there were some changes, but the concept and the bulk of the designs including the 7-door sluice, generally remained the same. The conservancy was developed with the aim of providing irrigation and flood control.
"Construction of the conservancy dam on the Abary has certainly changed the nature of the river," Camacho said in a recent interview with [This Publication]. "Seasonal floods when the river channel disappeared no longer occur, I have personal experience of this. During the construction period when I was the Consultant's Project Director responsible for supervision of the ongoing works our boat got its outboard motor caught on barbed wire fences on a few occasions, although we had experienced operators who knew the river channel very well."
Notwithstanding his statement the most recent flood in the Abary area was of such magnitude that residents recounted stories of driving their boats off of the river channel because the water was so high. Camacho surmised the river has now become a natural drainage channel for the area below the dam commanded by the main canal and for the west bank Abary. "It was considered that the tidal volume flowing in and out of the 35-mile long river channel from the estuary to the dam, twice a day, would be sufficient to keep the river channel effective as a main regional drain. It was anticipated that the upper third reach of the river would silt up, but that the hydraulic section in that area would still be adequate for drainage of the adjoining areas."
He said that after closure of the river in 1981/82 an echo sounding of the riverbed from the estuary to the dam was done to determine its levels at closure. The MMA/ADA was left with the record to make future comparisons, which would indicate the location and extent of siltation. He added that where silt is in excess it should be removed by the MMA/ADA.
Attempts to have this issue addressed by [This Publication] with MMA/ADA officials did not yield any result. Aubrey Charles, General Manager of the MMA/ADA scheme told [This Publication], "I am not discussing anything with the media and you can put that in the newspaper."
Camacho recalled the intent of the project was that water released from the Abary River Control sluice at 50 cubic feet per second would control saline intrusion and provide a supply from the river for pumped irrigation to the west bank of the Abary, from the dam to the Mahaicony Abary Rice Development Scheme (MARDS). "I do not know whether this has been implemented or is necessary," he stated. He also recalled that prior to closure of the river it could become brackish up as far as Onverwagt and occasionally in drought years as far as the Blairmont pump station. Onverwagt and Blairmont are approximately 12 miles and 18 miles from the Abary estuary respectively.
Residents and ranchers along the banks of the Abary noted that last December saline water was up the river affecting the water quality. In addition Malcolm Alli, an ex-Chief Hydraulics Engineer noted, "the 7-door Abary Control Sluice that I designed was built to control the water in the Abary River and to keep the river environment alive. To date I do not believe the sluice doors were ever opened to release a certain amount of water which was a requirement to keep the river alive. The doors are also leaking... At the moment the lower reach of the Abary River is silted up and not functioning as a river anymore."
Camacho's 1994 study "Policy and Environmental aspects of Water Control Schemes" on the current situation and operational status of D&I works noted that at that time the conservancy dam and control structures of the Abary Water Control Scheme were generally in good condition. Ally made his observations during the recent flood of 2005/06.
In the 1994 report Camacho, noted the present deficiencies in the Abary area. He stated there that recent surveys of the river outfall through the foreshore indicated the low flow channel was about 1.5 feet deep and about 50 feet wide and a comparison with the 1960 survey data on which the planning and design of the scheme was based, did not appear to show a significant change. However he later wrote that the water level appears to be about 1.5 feet lower than it should be at the dam, at Copeman and the reasons for this should be studied, using the hydromet and irrigation data collected during the first decade of operation and applying them to the model of the Abary Conservancy Behaviour.
He noted also that the sea dam adjoining the Abary sluice was too low and was in danger of being outflanked or becoming ineffective.
Included in the report was information that pumping from the Burma drain for irrigation of the Park-Abary area, a part of the original plan seems to have been abandoned and now, where possible, farmers pump from the drains to meet their individual needs. The internal works of the Park-Abary area were not inspected, but it is reported that they need reconditioning Camacho stated. Several farmers from the area have complained this year that in the dry weather they have to pump their own water into the fields and in the wet season are required to pump water out of their fields.
Referring to the aquatic growth in the creek, which only a few miles from the river control sluice makes the river impassable by boat, Camacho in the interview said this was there even before the project was started. "The water hyacinth and water grass were cleared by the people who used the river for transportation before the start of the project. Now they should be cleared by the MMA/ADA when the weeds reduce the required drainage capacity of the river for transportation."
Commenting on the aquatic weeds in his 1994 report, he had said they were encroaching on the sides of the Abary and are right across the river in the reach between Foulis and Golden Fleece [less than ten miles from the estuary]. This stretch must be kept clear, if necessary, using the barge with the Harbour Master outboard engine. If this is not done the drainage of a very large area could be adversely affected.
Indicators of a dead river
Dr Patrick Williams of World Wildlife Fund Guianas (WWF) said with regard to the present state of the Abary Creek, "if the river is dead it cannot sustain life forms. There are some indicators of a dead river; they are heavily polluted with algae bloom and are deficient of oxygen." He conceded the river in its present state has lost some of its life. "If the river changes its old regime then some of the fish and life patterns surrounding it will vary. This is because some species are more tolerant to certain conditions than others," Williams said.
Williams linked the presence of aquatic weeds in the river to what is happening in the drainage and irrigation system of the MMA. For instance the fertilizer run-off increases the profuse growth of vegetative aquatic life. "Damming of the river reduced the actual flow, contributing to blocking and increased sedimentation. There is also a strong tidal effect from the sea influencing the creek's ability to run off," he said and hence dense weeds.
A build-up of silt has caused the channel close to the river mouth to change one mile westward for the water to flow out, he stated. Williams mentioned cycles of erosion and accretion that also ultimately affects the flow of the river. He explained erosion would take the sediment out into the ocean while accretion would build the sediment up. The build-up of sediment would affect the regime of the river by affecting the speed at which the sediment moves. The river according to its flow would begin to drop off its load of sediment, as it would become more difficult for it to handle its load. The river would reach a stage where it cannot transport the same volume of water as it flows so much slower. Additionally the canals in the MMA are silted up and during the high tide there is no flow within a 12-hour period.
The Abary wouldn't be the first river that such concerns have been expressed about. The Konawaruk River was said several years ago to have been so badly polluted by gold mining that it was declared dead by nature lovers. The colour of its water had changed dramatically and it no longer hosted the wide variety of animal life previously seen.
Camacho said that in the planning of the conservancy, "it was not expected that the mouth of the Abary River would be silted up periodically or would require routine dredging." Rather it was considered that the tidal flow between the river mouth and the conservancy dam would set up a new regime on the river, which would allow it to function adequately as a tidal regional drain. This does not appear to have been the case as it has been generally accepted that the mouth of the river is silted up and needs to be dredged to improve flow capacity. This is to be done sometime this year.
Other commentators such as former Deputy Executive Officer of the Civil Defence Commission, Seopaul Singh, a letter writer in the [This Publication], suggested that not only the mouth of the creek is silted but along its entire 35-mile-long stretch. He added that, "Anyone who understands the natural flow of water, would have foreseen that damming the Abary River 35 miles upstream, would some day result in its silting up, if dredging at the mouth was not a regular feature of the maintenance regime." He noted also that historically and in reality, salt water overran the Abary River, which silted up especially at the mouth. "There is therefore a combination of human factors and natural factors working together to retard the rivers' flow," Williams stated.
An example of the effects a dam can have on a river are illustrated by Lake Nasser, Egypt. It is a man-made lake created by the construction of the Aswan High Dam, opened in 1971. The dam was built to regulate the flow of the Nile River, and thus benefit the region's inhabitants. Gone are the days when Egyptians worry that the Nile will flood too high, destroying their crops; or fall too low, not providing proper irrigation. The down side however is the Nile no longer flows strongly enough to keep salt water from the Mediterranean Sea forcing its way up the Nile. The salt water disrupts the animal habitat and sterilizes the soil in the northern delta region where the banks of the Nile are becoming badly eroded.
Charles Sohan another observer and commentator on the condition of the Abary River region during the floods wrote, "As a result of unusually heavy rainfall compounded with neglect and poor management the drainage system lost much of its efficiency to carry out its designed function effectively. Therefore, when the rains came the drainage channels could not convey their designed volumes of water to the Abary and other outlets in a timely manner and the huge volume of water just backed-up and spilled into the adjoining low-lying areas."
Dr Williams therefore suggested that ways of cleaning the outfalls have to be found as well as keeping the profile of the river by clearing it of its weeds. He attributed some of the impurities in the river to pesticides used to deal with weeds in the fields. The run-off of the pesticides in the water can affect the ecology of the area in addition to poisoning animals. The term 'dead zone' refers to the risk of death for many organisms living in an area where pollution has caused a reduction in the oxygen level. He also highlighted a need for more studies and research on river flows. "The MMA should have been taking/doing tests on the sediment load, checking the depths of the rivers at different times, studying the long and cross-profile of the river, testing for chemicals, which would tell how much fertilizer is affecting weeds, and testing for oxygen levels," said Dr Williams.
The Environmental Protection Agency was contacted by [This Publication] in an effort to obtain data it may have on the Abary River and any changes in its wildlife population and characteristics since the damming. However Executive Director Doerga Persaud said they have not received any complaints on matters pertaining to the Abary area. He noted that if anyone has any complaint "we would react, given the nature of the EPA. We encourage people to contact us." He noted that the agency would generally do tests and projects of an investigative nature where there are operations that affect the river.
A nature lover and frequent visitor to the upper regions of the Abary River who also said that his family has a 100-year history in the area but who did not want to be named said "the river is dead because the administrators have not honoured their obligations to the plans laid out by Ballast Nedam and Halcrow when they completed the scheme. This in turn has made the water downstream of the dam unsuitable for use by the residents of the Abary."
"I very much doubt," said Camacho, "that the instructions in the Operations and Maintenance Manual have been closely followed due to lack of the necessary funds. This is probably due to inability of MMA-ADA to collect rates for flood control, drainage and irrigation (FCDI) services, and also possibly, inadequate government subsidies." In his 1994 report this was one of the issues raised where he said, "cost recovery by the MMA/ADA for drainage and irrigation services is poor and people who can well afford to pay are not paying."
The local tourist said the river is a complete mess as it is being allowed to die slowly. The MMA, he said, suggested that persons clean the river themselves. "We have cleared the river for years." He then referred to tourists who were disgusted with the state of the river and added that the conservancy was also not in the best shape. A main canal which runs through the conservancy to a spillweir at Dageraad, West Coast Berbice and into the Berbice River is clogged more often than not according to Hemraj Kissoon, Managing Director of AH&L Kissoon Ltd. A photograph in the MMA/ADA's brochure shows the clogged canal leading to the spillweir
The naturalist mentioned above advocated that the authorities should release water from the conservancy and stated it was nonsense to say that the water could flood the area or that the doors to the conservancy were not working. On the first issue he pointed to the post-flood height of the creek, which on average is some two feet below the shoreline. So then why not allow some water to flow through? On the second issue of the conservancy doors reportedly not working he said they should be fixed urgently "What are they waiting for, a catastrophe to happen? The conservancy is now at its highest, use the water now to flush the river," he suggested.
The design of the Abary River Control Project says Alli, included a drainage discharge capacity of 900 cusecs from the conservancy to the Abary River during the rainy season to drain its command area without causing flooding of adjacent land.
The anonymous tourist revealed that he is well aware of all that goes on in the region. He noted that the vision behind damming the river for flood control, irrigation and drainage was correct. Regarding the ecology of the area he said it was a sanctuary for wildlife, such as the white beak peckery, skintabera, agouti, red deer, tapir, labba, caiman and wild birds which all use the conservancy. It is unclear how significantly these populations have been affected by the damming of the river.
On some eight trips to the Abary Creek area between January and March this year, [This Publication] observed that it has a brown trench-like colour suggesting that the water has higher levels of sediment than would normally be found in Creeks such as Mahaica and Mahaicony where the water is black even though these creek banks are more populated than the Abary Creek area.
Further, some sections of the Abary are difficult to navigate because of its vegetative overgrowth. In other words the grass in the creek has been allowed to grow freely making it resemble a regular trench as observed in other parts of the country. This is as a result of the altered water flow. Even though the Mahaica and Mahaicony have aquatic weeds the channels are naturally clear. In addition to the grass there is a particular part of the Abary Creek three miles from the conservancy dam at which in order for a boat with an outboard engine to pass, the propeller of the motor has to be lifted out of the water. If it were left down it would scrape the bottom of the creek damaging the engine in the process. On subsequent visits by [This Publication] persons who use the river for travelling had apparently cleaned this part of the Abary as the boat could once again pass freely. Regular visitors to the area told [This Publication] that members of the public with property in the area would occasionally clear the Abary of weeds, in particular water hyacinth or `Alligator spoon'.
Approaching the Abary Control Sluice [This Publication] observed that the river takes on a coffee black hue suggesting that it is more natural at this point than further downstream. Possibly the leaking observed at the control sluice allows for a minimal flow up to a few miles downstream.
Visitors to that region of the Abary Creek some three miles from the Abary Conservancy seven-door sluice said it was in a miserable state. They recalled that shortly after the completion of the project the sluice gates were opened occasionally to allow the river to be washed out but now this is not done at all.
They also referred to an event in the recent past where one of the owners of private property mobilized his resources to have the Creek cleaned in the vicinity of the residences there.
While it is clear that construction and operation of a reservoir can have a substantial effect on the stability of the river channel downstream from the dam what the authorities do not appear to have available is a comprehensive collection of data on the impact on wildlife and river characteristics.
Among the likely effects of the damming are that plant and animal communities adapted to still, warm water environments will replace those adapted to colder free flowing rivers. Fundamental changes in productivity, food chains and nutrient cycling will also occur.
It would seem with increasingly erratic environmental trends, issues relating to the stability of the Abary River channel including protection of riparian (of or on a river bank) resources, protection of habitats for threatened and endangered species, and bank stabilization as related to loss of property, general aesthetics and recreation need to be scientifically observed so as to maintain updated records on the status of the river and its environs which today are either non-existent or top secret.