Prediction Of Watery Environmental Effect Of And Measure Design For Construction Wastewater Of The Xiluodu Hydropower Station In The Jinsha River

Xiluodu Hydroelectric Project is a gigantic hydropower station in magnitude, with a major function of power generation and additional roles include sediment control, floor prevention as well as downstream navigation improvement. A national nature reserve i.e. National Reserve of Yangtze Rare Fish Species (H'e Jiang River to Leibuo Section) is located 1 km downstream of the dam site. Due to the long construction period and great amount of waste water discharge, if no proper treatments and/or approaches adopted, the obvious negative impacts on water quality of Jinsha River will be incured, and even worse, those normal functions of existing national reserve will be unbalanced accordingly. Therefore, accurate assessment including the magnitude and ranges of waste water discharge during construction period and establish an effective and reasonable mitigating approach for water quality protection are vital important, and it will play a very important role in maintaining the normal balance of the national reserve.The traditional predict/forecast of the waste water impacts in construction period was mainly focused on qualitative analysis or through zero dimension/one dimension models for rough calculations, therefore, quantitative calculation was rarely carried out. The above-mentioned analysis and model coould not meet the requirement of the assessment on waste water impact in construction period, so in this paper, twodimension water quality forecast model was introduced and adopted for carrying out more further and deep analysis of the impact in construction period. As shown in the predication, in August of flood season, the runoff had a maximum discharge, the dilution and pervasion abilities of the water mass reached the maximum degree. 10 km downstream of the batching plant wastewater discharging orifice, the SS recruitment amount could be reduced to 10mg/L or even lower. In March of the dry season, the runoff of the Jinsha had the minimum discharge, sayed 1310m3/s, so the dilution and pervasion abilities were the lowest around a year. The distance of same SS value removed downstream to 33km. In the other months around a year, the SS values and pervasion abilities were between the mentioned two cases above.In reference of the polluting characteristics in construction period, the detailed workmanship of wastewater treatment had been determined, the treatment of wastewater from the aggregates of the batching plant would be carried out by means of combination of flocculating settling, gravity thickening and filtering; the concrete washing water would be treated by sedimentation method; the wastewater of machinery repair and maintenance would be figured out by oil-isolating tank and the domestic sewage would be handled through treatment equipment. In this paper, the major parameters of workmanship were determined, and main structural dimensions were calculated. The research could be used in the environmental aspect especially in water quality improvement for Xiluodu Project and could be referenced by incoming project in future on the aspect of Environmental Protection Design (EPD).