Fluxes of Nitrogen, Phosphorus, and Dissolved Organic Carbon in the inflow of the Lehnmühle reservoir (Saxony) as compared to streams draining three main land-use types in the catchment

R Benning,K Schwärzel,K Schua,K H Feger

doi:10.5194/adgeo-32-1-2012

Abstract

Abstract. The aim of this study was to assess the impact of land-use on inputs of nitrogen, phosphorus, and DOC into the inflow of the Lehnmühle reservoir (drinking water supply). Land-use in the study area is dominated by forest, with smaller proportions of grassland and crops. Water quality was analyzed for the hydrological years 2010 and 2011 at the outlets of three small catchments with homogenous land-use (crops, grassland and forest) and at the outlet of the watershed. The highest nitrogen and phosphorus concentrations were observed in the streams draining the agricultural areas, and the lowest concentrations were found in the forest catchment. The DOC concentration was highest at the outlet of the watershed whereas the concentrations in the small homogeneous catchments were lower. The information collected about the land-use dependent matter exports in these study areas will be used for climate change impact modeling with the Soil and Water Assessment Tool.

Highlights

Water quality at the watershed scale is affected by various sources of biogeochemical fluxes, including pollution from either point or diffuse sources
The results of this study indicate that the export of N, P, and dissolved organic carbon (DOC) depends on the type of land-use
While the N exports are generated from diffuse sources, the P export pattern varied depending on the scale considered

Summary

Introduction

Water quality at the watershed scale is affected by various sources of biogeochemical fluxes, including pollution from either point or diffuse sources. Whereas pollution inputs from rural areas tends to generate from diffuse sources, which will be affected by the specific land-use type The municipal water supply for the German Federal State of Saxony is largely supplied by 22 drinking water reservoirs, which are mostly located in the Ore Mountains with watersheds characterized by rural land use typical of this region. Monitoring programs to observe water quality are carried out by the State Reservoir Administration of Saxony (LTV). Their observation points reflect river sections, and as a consequence the analyzed concentrations mostly represent a mixed signal of all land-use types within the upstream river basin To identify and balance matter inputs related to individual land-use types another approach is needed

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Conclusion