Water quality and plant species composition within Chemususu Dam, Baringo County, Kenya

Abstract

Chemususu Dam, a newly constructed dam, receives water through forest surface run-off and Barain and Sawich rivers. The aim of the study was to assess the water quality and plant species composition of Chemususu Dam. The study was carried out in a period of six month (August 2014 to January 2015). Sampling was done during the day and physico-chemical parameters of water were obtained using standard laboratory methods. The data was subjected to statistical analysis using computer package SPSS version 21 and significance difference between means was obtained using paired t-test. Water samples for phytoplankton identification were collected and 4% formalin was added for preservation. Whole plant. or shoot of macrophytes along the periphery of the dam were randomly collected at each sampling station and placed in polyethene bags. Mean temperature ranged from 17.02 QC in upstream River Sawich (Cl) to 21.48 QCin dam (C3). Median pH was between 6.77 in dam to 6.89 in upstream River Barain (C2). The mean conductivity values ranged between 63.67 ~S/cm in Barain river to 81.16 ~S/cm in dam, mean turbidity ranged from 3.12 NTU in dam to 94.82 NTU in Sawich river. Mean dissolved oxygen ranged from 4.2 mgll in dam to 6.1 mgll in Barain river; mean total dissolved solids ranged from 111.5 mg/l in downstream River Chemususu (C4) to 181.7 mg/l in Sawich river; mean nitrates levels ranged from 4.39 mg/l in Chemususu river to 5.26 mg/l in Sawich river; mean phosphates was between 3.34 mg/l in Sawich river to 4.5 mg/l in Barain river; mean sulphate was between 3.3 mg/l in Chemususu river to 7.2 mg/l in Sawich river; mean carbonates was between 4.17 mg/I in Barain river to 8.6 mg/I in dam and mean chloride ranged from 2.17 mg/l in Chemususu river to 2.73 mg/l in dam. Statistical difference" was recorded between turbidity of inflowing rivers; Cl and C2 (P= 0.007, T=4.4), in±lowing rivers and dam; Cl and C3 (P= 0.003, T= 5.5), C2 and C3 (P= 0.001, T=6.6), and between inflowing rivers and' out flowing river; Cl and C4 (P= 0.003, T=5.5), and C2 and C4 (P= 0.001, T=6.8) and phosphate levels between upstream rivers Cl and C2 (P= 0.025, T=-3.l6). Levels of nitrates, sulphates, total dissolved solids, pH and chlorides are within acceptable levels according to KEBS and WHO standards. However, phosphate levels were above the required 2.2 mg/l and turbidity of upstream rivers was higher than 5 NTD. Plant species were identified and confirmed using taxonomic keys. Three species of angiosperms and 19 phytoplanktons were recorded during the study period. Based on our results, it is concluded that the water quality of the dam is safe to be used for domestic purposes and agricultural activities if chemical concentrations do not increase. Regular monitoring of water quality is necessary to audit and assess to ensure sustainability of the dam.