gpa_east_africa_case.. - GRID Africa GeoPortal - UNEP

Source: Mwaguni & Munga 1997Sewage Discharge RatesDischarge Rates –cubic meters per daySource Design Flow Current Flow ProjectedChangamwe Stage 1 17 100 Unknown 51 300Kizingo 31 400 Unknown 94 200Environmental Impacts and Resources AffectedFresh water. Mombasa District has no surface water resources of its own. The Districtdepends on surface water supplies from Baricho in Malindi District. This source experienceslow flows during the dry season and siltation causes frequent breakdowns during the rainseason resulting into perennial water shortages in Mombasa. Groundwater sources is themain source of water supply to the population of Mombasa supplementing surface water, butdue to inadequate water management, lack of distribution infrastructure and proximity to humansettlements, ground water sources are saline or contaminated with feacal matter. Studies byMwaguni & Munga- 1993, 1997 and Mwaguni 1999, have confirmed that all ground watersources developed alongside human settlement did not pass the test for drinking water. Onlythose sources developed far away from human habitation passed the standards for drinkingwater. Since the largest number of the sources have been developed near or within humansettlements, treatment of such sources to make them potable is not sustainable because of thepresence of the permanent sources of contamination from pit latrines and soakage pits.Microbial contamination of ground water in Mombasa DistrictSource No Coliform count per100mlE. Coli count per 100ml Potability*WellsWellsBoreholesBoreholes203111#25-1800+0 – 417-1800+00-1800+00-500101Source: Mwaguni & Munga 1997* Potability: 0 - not potable, 1 - potable# Borehole water treated with ultra-violet radiationDrinking water standards applied in Kenya are: -(a) Coliform count < 10/100ml, (b) E. Coli count, nilMarine and Coastal Ecosystems. Important marine and coastal ecosystems on the KenyaCoast include: Coral reefs, beaches, mangroves, lagoons, coastal and Kaya forests, marine andinland reserves and historical sites. Coastal reefs support a rich diversity of species and protectthe shoreline from wave action. Mangrove habitat form important nursery grounds for a varietyof fishes and crustacean, for various species of sea birds, act as nutrient trap that help reducepollution loads to the marine environment in addition to providing stability of the shorelineagainst erosion. Biodiversity in intertidal mangrove forests is usually high. Between the reefsystem and the shoreline are the biologically productive lagoons, which are critical to fishingactivities. The sandy beaches and sea grasses are ideal for numerous marine creatures,providing nestling grounds for various species of turtles, fishes and mollusks. The lowland andKaya forests support a high diversity of flora and fauna.• Pollution from industrial effluents and sewage and development pressures create impactson these eco-systems leading to their degradation.• Snorkellers trample on coral reefs, the reefs suffer anchor damage in addition to sufferingthe consequences of degraded water quality through oil pollution, siltation and thedischarges of sewage.• Mangroves suffer from over-cutting, pollution from oil spills and waste dumping and fromthe effects of sedimentation and improper oyster harvesting. The consequences of this isthe decline of fuel wood and mangrove poles for building, loss of livelihood for mangroveharvesters and loss of breeding habitat for fisheries and associated impact on fish catch.Final Draft Report – Cost Benefit Case StudiesGPA Strategic Action Plan on Sewage, October, 200074