Environmental Assessment of the Chameliya Hydroelectric Project, Darchula during Construction Phase

Abstract

Environmental Assessment is the method to quantify the project induced impact on the environment. Monitoring is also essential aspect of environmental management in River valley project. Chameliya hydroelectric project (30MW) is six hours daily peaking run of river generating system, located in the Darchula district of Far Western Region of Nepal. The entire project structure lie along the Chameliya River bank, a distance of 4067m from weir to powerhouse. The broad objective of the study entitled “Environmental Assessment of Chameliya Hydroelectric Project, Darchula during Construction Phase” is to assess various environmental impacts vis-à-vis status of mitigation measures adopted by the project during construction period as recommended by EIA report. The research design involved both field work and laboratory investigations to generate analytical data for the accomplishment of objectives since 2009.

Flood frequency analysis has been conducted with 20 years of data using Gumbel’s distribution function. The design flood of 710m 3 /s has been worked out to be 50 years. All the physico-chemical parameters of Chameliya river water have been found within the limit to support the aquatic ecosystem of river. The study has revealed that there is small increment in pH, alkalinity and BOD but significant increment in some parameters such as Total coli form, conductivity, magnesium, sodium, and total dissolved solid with base line value. The values of TSP and PM 5 around the Audits and head works have been found to be higher than the NAAQS guideline values for 24 hours mean. Like wise, the increments in the TSP and PM 10 10 have been observed to be ten folds and four folds higher than the baseline values respectively.

The study has depicted that the average day time noise levels at the monitoring station except at the headwork were within the acceptable range set by W.H.O. Impact of Chameliya hydroelectric project on fishermen’s livelihood considering bio-physical and socioeconomic aspect has been assessed revealing a reduction in the over all abundance of fish fauna than the number stated in the EIA project report Project felled 3075 plants of 46 species which were higher than EIA report of CHEP. Impact on wild life was also investigated and the magnitude of impact is low, and site specific. The field study revealed that the mitigation measures except compensation for land, house, plant, fodder and physical structure, were partially complied and in premature stage but implementations of these were seen not satisfactory in accordance of EMP. Keywords: Environmental assessment, Chameliya hydroelectric project, flood frequency, mitigation measure, baseline value