The East African Crude Oil Pipeline (Eacop) will cross four major rivers and several wetlands in Uganda, while in Tanzania, river crossings will avoid contact with the main water systems, with the pipeline passing underground using horizontal directional drilling.
Sources say that despite approval of the Environmental and Social Impact Assessment (Esia) for the project, the choice of the least cost open-cut trenching method for river crossings in Uganda remains controversial, even among experts within government agencies that oversee wetlands.
Eacop officials say that long stretches of swamps in Uganda, which the pipeline will cross, dictated the use of open-cut trenching instead of horizontal directional drilling (HDD), with the contractor expected to trench the wetlands during the dry season to avoid construction-related pollution.
“HDD has its limitations,” said Joseph Mukasa Ngubwagye, Eacop’s environment and biodiversity field coordinator. “Of course, water courses are critical sites that the pipeline must avoid, but in this case, the risk is low.”
The pipeline will be buried 1.6-1.8 metres below the surface for open-cut trenching and 10 metres below the surface at two water crossings in Tanzania, where HDD is deployed, while for national roads and rail infrastructure, the project will use auger boring technique, at 2.5 metres below the surface, Lawrence Ssempagi, Eacop project compliance lead said.
The water course crossings in Uganda include the Kafu River between the Hoima and Kakumiro districts, the Nabakazi River between the Mubende and Gomba districts, the Katonga River between the Gomba and Ssembabule districts, and the Kibale and Jemakunya Rivers in Kyotera district, all draining into Lake Victoria.
The Eacop Esia says Nabakazi and Katonga are legally protected areas of high sensitivity that support species of conservation importance, for which industry standards recommend the use of harm-mitigating horizontal directional drilling to cross the water courses.
But Mr Ngubwagye said that the open-cut option will adequately mitigate the risks in these sites.
“If you are drilling a distance of more than one kilometre in a wetland, HDD gets more challenging,” he says. “What we will do with open-cut, is to make sure we do it in the dry season, string the pipes together on the ground, bury them, and cover the trench. Crossing works should take not more than one week.”
In Tanzania, however, the environmental watchdog insisted contractors use horizontal directional drilling to cross the Kagera and Sigi Rivers after oil spill simulations that were done showed that Lake Victoria is more likely to be polluted if there is a leak at the Kagera River crossing, experts told The EastAfrican.
“Perhaps Uganda wasn’t very strong on demanding that HDD be used. Experts advised Nema to ask the Eacop developers to use HDD in Uganda but because the open cut is the least cost, that option was chosen,” said Africa Institute for Energy Governance’s Diana Nabiruma.
“It could also be that the river crossings in Tanzania are considered more sensitive,” she added.
The Esia for Tanzania notes that the impact on sensitive water bodies includes aquatic habitat loss and disturbance to fish and aquatic macro-invertebrate species of conservation importance inhabiting the Kagera, Pangani, and Sigi Rivers, Lake Victoria and Wembere Wetlands, and ephemeral water courses.
An audit of the Eacop Esia in 2021 by a coalition of civil society organisations discovered that the developers preferred open-cut trenching because of its simplicity and low cost, warning that deploying this method did not equate to international best practices for these crossings.
“Choosing the open-cut method had been made by oil companies based on cost as opposed to environmental protection. Thus, a more environmentally friendly method, notably, HDD was proposed by the coalition,” reads the audit submitted to Nema.
In response, the Eacop developers made assurances that the appropriate technique would be based on a systematic assessment of each site based on its ecological value, including presence of species of conservation concern, protected and iconic species.
The developers also said they would review site-specific water course and wetland crossing methods based on their social attributes like community water use, wetland resource utilisation, and commercial use like fishing activities. However, the Esia notes that generally, the rivers within the Uganda section of the pipeline are so narrow that an oil spill would cover the entire river surface, and the pour point temperature of 40°C means the oil will solidify in the water, hence minimise the spreading of oil. Uganda’s low sulphur crude will require 40°C-50°C heating in the pipeline to flow.
“The oil will quickly become extremely sticky and would therefore — in solid form— either adhere to the riverbanks or the vegetation. In this solid state, the oil will quickly introduce a “barrage effect” that will further reduce drift and spreading, particularly in narrow areas of the rivers. The narrowness and curvature of the rivers and the small discharge contribute to the high retention of oil near the spill” the Esia shows.
This modeling suggests that at four of the five crossing locations, the modeled length of the river affected ranges between 0.6km and 3.0km. The relatively short transport distances are attributable to the high viscosity of the oil and the curvature of most of the rivers.
The other sensitive ecosystem that the pipeline route crosses is Taala Forest Reserve in Kyankwanzi district. Taala is a legally protected and nationally recognised area, and officials say part of the section that would be impacted is already degraded but will be restored after pipe laying.
Eacop also changed the course of the pipeline route by 200 metres, to avoid Wambabya Forest Reserve in Hoima and Kikuube districts, after environmentalists criticised the project for traversing and impacting this protected area.