Water Quality and Land Use Changes in the Alafia and Hillsborough River Watersheds, Florida, USA¹

Abstract

Spatial distribution of land use can have a substantial effect on surface and groundwater quality. Our objective was to test for trends in flow components and water quality related to changes in land use in the Alafia and Hillsborough River watersheds in Florida, USA, over the period 1974‐2007. In addition, water quality statistics were evaluated in the perspective of numeric water quality criteria and proposed reclassification of segments of the Alafia River. Trends in 10 water quality parameters and three discharge variables were evaluated using a nonparametric trend detection test. Results of land use analysis indicated substantial urbanization and loss of agricultural land in the study area. Discharge variables did not exhibit significant trends, whereas trends in the majority of water quality concentrations were negative or nonsignificant with total nitrogen and total Kjeldahl nitrogen as exceptions showing positive trends. Changes in nutrient pathways could not be clearly identified. Considering recently promulgated numeric nutrient criteria and standards for dissolved fluoride, much of the Alafia River was found to be out of compliance. While there were land use changes and changes in water quality over the study period, it was difficult to identify a direct cause‐effect relationship. Responses to regulatory efforts, such as the Clean Water Act and improvements in phosphate mining practices, may have had greater impacts on water quality than changes in land use.

Influence of Land Use and Point Source Pollution on Water Quality in a Developed Region: A Case Study in Shunde, China

“…This is consistent with previous studies which indicate that an impervious surface plays an important role in reducing water quality in adjacent aquatic systems [ 7 , 8 , 20 , 23 , 24 ]. An impervious surface can change natural hydrological conditions by increasing the volume and the velocity of storm runoff [ 25 ] and preventing natural percolation [ 22 ]. Storm runoff in urban areas contains various pollutants from residential and industrial areas [ 26 , 27 , 28 ], flows into rivers and reduces water quality [ 29 ].…”

Evidence of Phosphate Mining and Agriculture Influence on Concentrations, Forms, and Ratios of Nitrogen and Phosphorus in a Florida River

“…Phosphorus fertilizers from phosphate-mining are one of the major P sources of coastal eutrophication, but surprisingly less is known on how phosphate-mining affects nutrient export to receiving waters relative to other land-use activities [14]. Phosphate-mining has a long history in Florida, United States [15].…”

“…Because runoff from mining operations may influence the hydrology, water quality, and habitat loss, the Florida Legislature requires that all lands mined for phosphate after 1 July 1975 be reclaimed [15]. A recent examination on water quality changes in two watersheds of central Florida showed consistent decreases in total P (TP), but TP criteria violations were still severe [14]. Little is known about the forms and sources of P in phosphate-mining watersheds, which is essential for further improvement for the mining reclamation.…”

Effects of Landscape Development Intensity on River Water Quality in Urbanized Areas

“…Under the influence of urbanization, non-point source pollution caused by rainwater runoff has become one of the important reasons for the deterioration of urban water environment [15,16]. Water quality parameters such as total soluble solid (TSS), chemical oxygen demand (COD MN ), total nitrogen (TN), ammonia nitrogen (NH3+-N), and total phosphorus (TP) are representative pollutant parameters, which describe the physical and chemical characteristics of water bodies, have attracted more attention in water quality studies in urbanized areas [17][18][19][20][21][22].…”