Study On The Relationship Between Landscape Pattern And Water Quality

Songhua River Basin is an important water area in Heilongjiang Province.The water quality problem is becoming more and more serious.The natural resources in the basin are rich.With the acceleration of urbanization,the landscape pattern around the basin is changing,which has significantly affected the water quality of the basin to a certain extent.In recent years,the problem of landscape Bureau and water quality has become a hot topic.This paper mainly discusses the landscape pattern,water quality index and the relationship between them.In this paper,the data of remote sensing images in 2009,2014 and 2017 are selected,and the methods of image geometric correction and radiometric correction are carried out.The water quality index data from 2009 to 2017 are selected for screening and treatment.Under the application of envi5.3 and ArcGIS 10.2 software,three remote sensing images were processed,and the landscape types were classified by remote sensing means.The landscape patterns of the five buffer zones of 100 m,500 m,800 m,1000 m and 2000 m in Harbin section of Songhua River Basin were preliminarily extracted and analyzed by FRAGSTATS 4.2 software.The correlation analysis and redundancy analysis between different landscape indexes and corresponding numerical indexes can further analyze the relationship between landscape pattern indexes and water quality indexes,and analyze the specific relationship between landscape pattern indexes and water quality indexes.The main conclusions are as follows:(1)Water quality characteristics: the water quality of Harbin section of Songhua River Basin is generally better.In terms of time,the water quality indicators in 2017 are better than that of other years.In terms of space,the concentration of permanganate index is the highest in the inner section of Ashe River Estuary,reaching class IV water quality;the concentration of permanganate index is the lowest in zhushuntun section.Generally speaking,the water quality indexes of Ashe river mouth and Hulan River mouth are worse than other sections,and zhushuntun section is the best.(2)From 2009 to 2017,in terms of landscape type,the CA of construction land(total area of patch type)reached the maximum value in 2017;the CA of grassland reached the maximum value in 2009;the CA of forest land increased first and then decreased;the CA of water area was relatively stable with little change in recent years.The cohesion value of water area is larger than that of other landscape types at each buffer scale.AI(aggregation degree)of construction land is increasing year by year,with the largest AI value in 2017.The AI of grassland decreased year by year,indicating that the aggregation degree of grassland was decreasing.At the landscape level,the overall LPI(maximum patch index)in 2017 is greater than that in 2009 and 2014.In each year,the CONTAG(spread index)value of 100 m buffer is greater than that of 500 m,800m,1000 m and 2000 m buffer,and shows a decreasing trend.SHDI(Shannon diversity index)and SHEI(Shannon evenness index)are the largest at the buffer scale of 2000 m and the smallest at the buffer scale of 100 m.In 2014,the value of IJI(scatter and juxtaposition index)in each scale was higher than that in 2009 and 2017.(3)Impact of landscape pattern and water quality: at the type level,the cohesion and AI index of water area,forest land,cultivated land and grassland are negatively correlated with the concentration of each water quality index in 100 m buffer zone.The cohesion and AI index of construction land are positively correlated with the concentration of each water quality index.After 500 m buffer zone,the cohesion of grassland and construction land has a positive correlation with water quality index,and with the increase of buffer zone scale to 1000 m,the correlation is more obvious.At 2000 m buffer zone,the correlation is weakened.At the landscape level,SHDI,SHEI and IJI were positively correlated with water quality indexes,while LPI and contract were negatively correlated with water quality indexes.In 500 m buffer zone,SHDI,SHEI and water quality indicators are still positively correlated,and the correlation is better than that in 100 m buffer zone.In 800 m buffer zone,SHDI,SHEI,Iji and water quality indicators are positively correlated,while LPI and water quality indicators are negatively correlated.In 1000 m buffer zone,the positive correlation between SHEI index and CODmn is the strongest,and the correlation between other indexes and water quality index concentration is also increasing.At 2000 m buffer zone,the correlation between each index and the concentration of water quality index is decreasing.