| River ecological evaluation plays an essential role in river management and restoration.Economic evaluation in river area,habitat monitoring and biological monitoring can be references for evaluation on effects of river management and river restoration.This paper studied the benefits of the Comprehensive River Ecological Restoration in the Pingliang Liangcheng Section by analyzing the hydrological data from Pingliang Hydrological Station and the Kongtong reservoir hydrological station)and combining the measured data(GPS positioning,river section water quality,river reed biomass,etc.),images Data(satel ite image maps)and survey data(social survey questionnaires)to analyze the comprehensive benefits of the“Comprehensive River Ecological Restoration in the Pingliang Liangcheng Section”.The main findings are:(1)The overflow weirs greatly improved the water ecological environment of the Jinghe River,resulting in smal er stream gradient,lower flow rate and better river connectivity.The large wetland contributed to the biological diversity in the river course.By the end of 2016,there were 9 overflow weirs in Pingliang Liangcheng section of Jinghe River.The water area formed by the overflow weirs reached 14.5838 hm~2(2)“Comprehensive River Ecological Restoration in the Pingliang Liangcheng Section”contributed to larger water storage area,higher water quality,better river connectivity,great reduction of channel bifurcation phenomenon and larger vegetation coverage.The planting area of artificial vegetation in rivers was 90.63 acres in April,2012,and,reached 1,608.98 acres in November,2016.The increase of vegetation area improved the quality of urban ecological environment to a certain extent.(3)1608.98 acres of the vegetation area was increased in the river between the Kongtong reservoir dam and the estuary of the Dacha river during 2015 and 2016.In 2015 and 2016,the water consumption during the growth period of reed was 4.82×10~5 m~3 and 4.91×10~5 m~3,respectively,accounting for about 0.43%and 0.44%of the annual runoff,respectively,provided the growth period of reed was every year from May to September.(4)The main variation of biomass in reeds was moderate.The semi-variation function model is a nugget model with a large range of variation due to some random factors,including runoff,precipitation,temperature,irrigation,and engineering construction.The total biomass of river reeds was 4.14×10~5 kg in 2015,and 6.23×10~5 kg in 2016.(5)The runoff volume was unevenly distributed in Pingliang Liangcheng section of Jinghe River during the year.The average annual runoff was 1.15×10~8 m~3,of which the runoff from July to September accounted for 43.12%of the total annual runoff.The interannual variation of runoff is larger,with two significant flood periods from 1974 to 1981 and from2011 to 2014.A small abundance of abundance alternated between 1982 and 1994,and a significant dry period from 1995 to 2010.The main factor influencing the runoff in the study area is the runoff volume of the Kongtong Reservoir Station,and the correlation between them is 0.917.In addition,the involvement of human activities also has an impact on the changes in runoff.(6)The water quality data of 2016/8/10 and 2016/11/23 are analyzed by principal component analysis.It shows in 2016/8/10 the worst water quality section is Shuangqiao Road overflow weir head section and Dachahe estuary section and in 2016/11/23 the worst water quality is Dachahe estuary and Double Bridge Road overflow weir head.It is considered that the quality of the rear stil ing pool of Shuangqiao overflow weir is better than that of Shuangqiao overflow weir head.The water quality at the outlet of the Eight Mile Bridge reed is better than that of the inlet.The construction of overflow weir and the reed planting on the river have an obvious purification effect on the water quality.(7)Residents have a high degree of satisfaction with the implementation of the river ecological comprehensive improvement project in the Pingliang section of the Jinghe River.Judging from the comprehensive evaluation value,the score is 4.0986,which general y meets the criteria of“extremely satisfactory”;the degree of satisfaction in terms of river flatness,flood safety,surface water increase rate,and vegetation increase rate is relatively high,but it is also not very satisfactory.In terms of water quality and water quantity,some of these are caused by social factors and there are also aspects that need to be strengthened. |
