Impact of riparian zone protection from cattle on nutrient, bacteria, F-coliphage, and loading of an intermittent stream

J Environ Qual. Jul-Aug 2012;41(4):1301-14. doi: 10.2134/jeq2011.0407.

Abstract

This 5-yr study compared, via an upstream-downstream experimental design, nutrient and microbial water quality of an intermittent stream running through a small pasture (∼2.5 animals ha) where cattle are restricted from the riparian zone (restricted cattle access [RCA]) and where cattle have unrestricted access to the stream (unrestricted cattle access [URCA]). Fencing in the RCA excluded pasturing cattle to within ∼3 to 5 m of the stream. Approximately 88% (26/32) of all comparisons of mean contaminant load reduction for lower, higher, and all stream flow conditions during the 5-yr study indicated net contaminant load reductions in the RCA; for the URCA, this percentage was 38% (12/32). For all flow conditions, mean percent load reductions in the RCA for nutrients and bacteria plus F-coliphage were 24 and 23%, respectively. These respective percentages for the URCA were -9 and -57% (positive values are reductions; negative values are increases). However, potentially as a result of protected wildlife habitat in the RCA, the mean percent load reduction for for "all flow" was -321% for the RCA and 60% for the URCA; for , these respective percentages were -209% (RCA) and 73% (URCA). For "all flow" situations, mean load reductions for the RCA were significantly greater ( < 0.1) than those from the URCA for NH-N, dissolved reactive phosphorus (DRP), total coliform, , and . For "high flow" situations, mean load reductions were significantly greater for the RCA for DRP, total coliform, and . For "low flow" conditions, significantly greater mean load reductions were in favor of the RCA for DRP, total P, total coliforms, fecal coliforms, , and . In no case were mean pollutant loads in the URCA significantly higher than RCA pollutant loads. Restricting pasturing livestock to within 3 to 5 m of intermittent streams can improve water quality; however, water quality impairment can occur if livestock have unrestricted access to a stream.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Husbandry
  • Animals
  • Bacteria / isolation & purification*
  • Cattle*
  • Coliphages / isolation & purification
  • Environmental Monitoring
  • Geologic Sediments / microbiology
  • Nitrogen / chemistry
  • Phosphorus / chemistry
  • Rivers / chemistry*
  • Rivers / microbiology*
  • Soil Microbiology
  • Water / chemistry*
  • Water Microbiology
  • Water Pollutants*
  • Water Pollution / prevention & control

Substances

  • Water Pollutants
  • Water
  • Phosphorus
  • Nitrogen