Small reservoir effects on headwater water quality in the rural-urban fringe, Georgia Piedmont, USA

摘要: Abstract Small reservoirs are prevalent landscape features that affect the physical, chemical, and biological characteristics of headwater streams. Tens thousands small reservoirs, often less than a hectare in size, were constructed over past century within United States. While remote-sensing geographic-mapping technologies assist identifying quantifying these features, their localized influence on water quality is uncertain. We report year-long physicochemical study nine (0.15–2.17 ha) Oconee Broad River Watersheds Georgia Piedmont. Study sites selected along an urban-rural gradient with differing amounts agricultural, forested, developed land covers. Sites sampled monthly for discharge inflow/outflow parameters (temperature, specific conductance, pH, dissolved oxygen, turbidity, alkalinity, total phosphorus, nitrogen, nitrate, ammonium). proportion cover watersheds had positive correlations reservoir conductivity values, agricultural forested covers showed (positive negative, respectively) conductivity. The majority outflow temperatures warmer inflows all uses throughout year, especially summer. Outflows lower nitrate concentrations, but higher ammonium. type structure was also influential; top-release dams oxygen pH bottom-release dams. Water effects still evident 250 m below dam, albeit reduced.