EVALUATION OF THE EFFECTS OF POPULATION GROWTH ON WATER QUALITY IN A MOUNTAINOUS WATERSHED

Degradation of water quality has become a key environmental issue over the past 40 years in the United States. While there has been great progress in cases where the sources of the degradation could be clearly identified (point sources), the effect of non-point sources, particularly those from anthropogenic sources, has proven more difficult to identify and quantify.

The major objective of this study is to evaluate the impact of population growth on the water quality in a specific mountain watershed. We have chosen one typical Jefferson County watershed (Turkey Creek Basin) where population has more than doubled in the past 25 years and is projected to double again in the next 20 years. Water analyses have been collected from this watershed over the past 25 years, documenting the changing water quality. The data from this populated watershed is compared to analogous watersheds with little population growth to quantify possible distinctions in water quality and chemistry.

Preliminary interpretation of the data from 1975 to 2000 for the TCB watershed shows an increase in total dissolved solids (TDS) in the surface water by a factor of three, with almost no change in the ground water. The analogous watersheds with little population growth show little change in TDS over the same period. Thus, surface water quality as measured by TDS is being significantly impacted by population increases in the watersheds. Studying the relationship between the ground and surface waters will help determine the various potential sources of impact (e.g. septic tank effluent, transportation corridors, construction activities, agricultural and livestock activities, etc.) affecting the populated watershed.

Comparing baseline studies from predevelopment years with studies completed recently should help identify the sources of the TDS increase and suggest mechanisms to attain a sustainable balances between population growth and water quality in mountainous watersheds. Studies such as this are necessary to identify the anthropogenic effects that have directly changed the water and to reduce the negative effects of human communities through sustainable development. Using the insights gained from this study, we can predict probable future impacts of growth on water quality for other mountainous watersheds.