EFFECT OF CHANGING LAND USE LAND COVER ON WATER QUALITY IN A RAPIDLY GROWING METROPOLITAN COMPLEX.
The Galveston watershed (Texas) consists of two of the largest cities in the US, with a growing population predicted to double by 2050. The continued development and urban sprawl is threatening water quality in the rivers, streams and tributaries that lead to Galveston Bay. Herein we used six land use land change (LULC) maps generated using the National Land Cover Database (NLCD) and NOAA satellite imagery data respectively from 1992 to 2011 and 30 years of water quality data to determine the current pressure on the bay from this developing watershed. The land cover data was collected for six major categories including: agriculture, forest, grass, developed, water and wetlands. These categories were then further subdivided into more specific land cover types. The water quality data was averaged over the 5-year span prior to creation of each land cover map. To test our hypothesis that changes in land cover type influence changes in the water quality parameters within Galveston Bay we used the multivariate statistical tool PRIMER with the PERMANOVA add on package. The analysis in found that an increase in the developed land water land type within the Galveston Bay watershed was positively correlated to an increase in salinity and negatively correlated with the nutrient concentrations measured within the Bay. The amount of agricultural, forested and wetland land cover have decreased between 1996 and 2011. There is a concurrent positive correlation with nutrients including total phosphorus, nitrate plus nitrite and total organic carbon in water quality associated with the loss of these green spaces. Continued growth is pushing this system to a possible tipping point.
Quigg, A., Texas A&M University at Galveston, USA, firstname.lastname@example.org
Steichen, J., Texas A&M University at Galveston, USA, email@example.com
Windham, R., Texas A&M University at Galveston, USA, firstname.lastname@example.org
Williams, A., Texas A&M University at Galveston, USA, email@example.com
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