Dredging the River Niger: The way forward
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The 653- pages- EIA Draft Report on the dredging of River Niger comprising volumes 1and 2 was completed and, possibly, submitted in October 1999. The project, by a commissioning letter dated 15 February, 1999, was "to carry out the Environmental Impact Assessment (EIA) of the proposed plan by PTF to dredge the lower Niger Waterway... The project covers about 572 km of the lower Niger, extending from Baro in Niger State to Warri Bifurcation in Delta State."
The State of Anambra, Delta and Kogi have each eight L.GA. to be affected by the dredge directly; Edo, has three LGA; Niger two LGA; and Bayelsa and Rivers, one LGA each. The idea of dredging of River Niger from Baro in Niger State to Warri in Delta State is a very good one but it must be done properly, using a well -produced and- evaluated EIA Report. After the submission of the Draft Report, in October 1999, it is believed that an in -house review must have been conducted and a Technical Review Committee appointed with copies of the report made available as widely as practicable for corrective inputs and suggestions to be made.
These report were supposed to have been displayed at locations to facilitate review by interested stakeholders, local government officials, NGOs and the general public... availability of the report at these location are publicized through newspaper advertisements, radio and television announcements." Public display and public hearings were supposed to have been encouraged. The outcome can range from a complete rejection through acceptance subject to some additional studies being undertaken to outright acceptance " before the dredging -project- execution may be carried out or projected. One thinks that this is where the country is now with regards to the River Niger dredging since the EIA Report evaluation is still in progress, and to be completed. One believes that the Ministry of Environment through the EIA Review Panel headed by Dr. Bukar Shuaib should be given a chance to complete action on the Draft Report.
It, therefore, follows that the dredging contract already awarded by the Abdulsalami Abubakar regime is highly - premature and must be revisited and reviewed. The process of the EIA for the dredging of the River is still in progress. It must not be short-circuited or aborted because of a hurriedly awarded N10 billion contract. Any half- hearted or incomplete EIA exercise or poor implementation process may be disastrous to the environment on the long run.
The present destruction case is an example of environment disasters from oil industry activities in the Niger Delta; or flooding, soil and gully erosion in southeastern Nigeria as a result of mismanaged development should show us all Nigerians the havocs caused by non-appreciation of serious EIA for any sustainable development. Let us not ever again cut our environmental nose to spite our face. Any environmental damage exposes our present and future to hopelessness. Despite the fact that the EIA Draft Report on the dredging exercise is quite detailed and is a fairly-good one, it has flaws, and weaknesses, and seriously neglects many sensitive aspects or areas of the threatened Nigerian environment.
These weaknesses and lapses should be considered for remedy to ensure that the planned dredging exercise succeeds. There were obvious neglects of the effects of the Anambra, Idemili and Orashi River Basins; the geologic and hydrogeologic phenomena; and the potential toxicity of River bottom sediments. People’s participation in project activities is not as widely- detailed and publicised as it should be. Floods soil and gully erosion disasters that would be exacerbated within Anambra Basin in Kogi and Anambra State did not receive enough evaluation. The Draft Report briefly described the geology along the dredge path but geology implications are not fully - appreciated. The Basement Rock along dredge flow may be fractured, faulted and jointed with potentials for rock falls, slides or engineering failures.
The excavated sand areas may be equally exposed to increased soil and gully erosion, and landslides. Possible encounters of mineralised geologic members such as coal, limestone, hydrocarbons, trace elements, heavy metals, etc. may result. The component of high water- bearing confined deep aquifers that may be cut across by the dredging seems not to be realised in the Report since the emphasis tended to be on watertable or unconfined aquifers. Intersection of pressure aquifers may result in high water flows into River with concomitant slope failures or slides of riverbanks. Exposure of mineralised geologic materials may result in creation of continued leachates or inputs of pollutants or contaminates into the River from such point sources. Such sources should be critically- identified and remediation action taken. Also care should be taken in dredging across faulted rocks and severe fractures to avoid sudden rock falls or slides or other accidents.
Even though the Report shows that there were extensive sampling of soils and river water for physicochemical analyses, the bottom sediments of the River seems omitted from the sampling. Bottom sediments if sampled at various depths, would be able to give a clue to possible presence of heavy metals, some of which may be toxic. For a river like the Niger which drains large, long and extensive basins of various soil/rock types in over six countries, and of immense ecologic variability, the presence of heavy metals in bottom sediments may not be ruled out. The physiochemical properties of such dredged waste spoils that include bottom sediments are incomplete without the characterisation of possible presence of heavy metals.
The disposal sites as recommended in the Draft Report are not acceptable. Many of them are located too close to the River and their sediments shall eventually be washed back into the River. It is not also acceptable to deposit them on farm lands if we accept the fact that the dredge spoil may be polluting or contaminating disposal sites, far away from the River Niger and its tributaries, should be located and proper chemical engineering waste disposal mechanisms employed. The Anambra River Basin is riddled with gullies and erosion- cayons. Some of the treated dredge waste/spoils can be transported away and dumped into gullies where these can be used to fill them and reclaim the land from the raging and advancing gullies.
Despite the fact that sight of the twenty-one LGAs of Anambra State shall be directly affected by the dredging project, there was an obvious neglect or omission by the Consultants in appraising the effects of the environments Anambra, Idemili and Orashi River. Heavy loads of sediments are trucked down by gully erosion into the River Niger yearly from uplands by these rivers, particularly, the Anambra River. The catchment areas of these rivers are heavily-built up; the soil and geologic units have easily-erodible components; average annual rainfall is over 2000mm; intense agricultural activities and fertilizer applications are carries urban and rural areas. Floods, soil and gully erosion, and environmental denudation transport sands, clays, pollutants and contaminant into the River Niger through these tributaries.
The Anambra Basin supplies quite a load of sediments and waste products into the Niger Delta yearly The dredging of the River Niger shall obviously exacerbate incidences of soil and gully erosion and sediment deposition in Anambra and Kogi State unless something is positively done to check them upstream of the Anambra Basin. As at now, the dredging project Report is silent over these issue. What shall be their fate then? There is a great need to evaluate the effects of the dredging on the dams upstream of the River Niger, particularly, the Kanji Dam areas. The new higher water flows that may result after dredging may cause drastic falls in reservoir-water levels and increased siltation of the hydroelectric dam. These may adversely eventually affect the energy-generation capacity of the dam. Hence, there may be need to dredge the Kanji dam as well, probably, later to avoid future problems. The dredging of the Kanji Lake is, even, long overdue, and should be recognised as such engineers, environmentalists, etc.
The already-awarded dredging contract should be revisited, recalled, redesigned and recosted with the new ideas and findings incorporated and new ideas and new dredging project targets set. While ensuring that Nigeria Inland Water Authority (NIWA), is fully involved, all the affected State and their State Environmental Protection Angelicas (SEPA), are made full participants at various levels. Adequate compensation must be worked out and paid fully to those affected. Soil and gully erosion upland of Anambra River Basin must be controlled. It is believe that when the new findings incorporated and approved, it will be possible to start the dredging of the River Niger with national support and acceptance sometime later next year.