Initial Assessment of EIA for Don Sahong Hydropower Project. Environment Programme Mekong River Commission Secretariat. Water quality and aquatic ecosystem health. Technical Consultation for Don Sahong Hydropower Project 07 March 2014, Vientiane. Impacts on environmental flows?
Mekong River Commission Secretariat
and aquatic ecosystem health
Technical Consultation for Don Sahong Hydropower Project
07 March 2014, Vientiane
Water quality during construction?
Water quality in the head pond/impoundment?
Water quality during flushing?
Water quality during decommission?
Impacts on sediment balance? (IKMP)
Impacts on nutrient balance?
Impacts on fish migration, both upstream and downstream passage? (FP)
Impacts on habitat continuity (fragmentation)?
Impacts on wildlife?
Impacts on tourism?
Impacts on health and livelihoods? (BDP)
This assessment is based on:
Environmental Impact Assessment Report, Final, January 2013 (EIA)
Engineering Status Report, Volume 1, 27 Sept. 2011 (ESR)Relevant environmental issues
#1: Assess the impacts of and on the project from selecting a minimum flow over KhonePhapheng of 800-1,224 m3/s and assess the impact of climate change on the flow over KhonePhapheng.
#2: Assess impacts on water quality from loss of sediments during excavation and deposition.
#3: It seems justified not to anticipate any water quality deterioration in the head pond.
#4: Investigate potential impacts from sediment flushing on the dolphin deep pool immediately downstream of the dam using 2-D or 3-D hydraulic models.
#5: Assess short-term consequences of increased sediment concentrations if blasting of structures during decommission take place.
#6: It is unlikely that impacts on the nutrient balance (although not addressed by the EIA) will occur.
#9: Due to the physical characteristics of the project it is not expected that discontinuity of habitats will be an issue (other than fish migration)
#11: Assess impacts on visual appearance and tourism of flow over KhonePhapheng of 800 m3/s. Up-to-date data on tourist arrivals should be used.
The EIA briefly compares some alternative projects of which the most developed option is the Thakho project but the assessment of this project seems to be based on a report from 2004, instead of more recent information such as IEE of 2009. International practice suggests that alternative projects be analysed in more detail.
#13: Compare the DSHPP with the Thakho project alternative, using up-to-date information for the Thakho project.Alternative options
Thank you…. the most developed option is the Thakho project but the assessment of this project seems to be based on a report from 2004, instead of more recent information such as IEE of 2009.