Restoration status of Nakayiba wetland, Masaka, Uganda

Many wetlands in Uganda have been converted into uses that are injurious to nature. However, besides just a few of them being restored, the success of restoration for any of them has not been assessed to guide future restoration efforts in the country. The study evaluated the restoration status of the Nakayiba wetland that serves the function of filtering the partially treated municipal wastewater in Masaka District. The focus was on key vegetation and water quality attributes. Plant recolonization status along the wetland was followed using quadrats (4m2) while pollution attenuation capacity was evaluated at the main inflow (confluence) and outflow using appropriate meters and lab analyses. Plant recolonization was not even; vegetation in the wetland was mainly dominated by Impatiens tinctoria (40.7%) although the upstream (42.8%) and midstream portions (36.1%) were mostly covered by Cyperus latifolius. Other major plants present included Cyperus papyrus (9.7%) mainly downstream (18.3%) and Typha latifolia (1.8%) found only downstream. Water quality studies showed significant (p<0.05) reductions in the physico-chemical parameters. There was high phosphorus retention at 87% total phosphorus (TP), and 92% Ortho-phosphates (- PO4 3- ) but low nitrate retention, NO3- (24.4%). Furthermore, fecal coliforms (FC) reduced from 9160 to 350 CFU/100 ml representing a 96.18% retention capacity while pH varied between 6.43 and 6.0 and electrical conductivity reduced from 811 to 280 µS/cm. Results indicate that Nakayiba wetland is steadily recovering and contributing to removal of nutrients and feacal coliforms, thereby improving water quality for downstream users. It is recommended that the municipal authorities should ensure that Nakayiba wetland is not re-encroached to allow for full recovery.