02510nas a2200205   4500008004100000245013400041210006900175300001300244490000700257520182000264653001402084653002202098653001902120653002102139653002502160100001902185700001602204700001802220856006602238       2009                        eng d00aStream discharge and riparian land use influence in-stream concentrations and  loads of phosphorus from Central Plains watersheds0 aStream discharge and riparian land use influence instream concen  a552 -5650 v443 a<p>Total annual nutrient loads are a function of both watershed characteristics and the magnitude of nutrient mobilizing events. We investigated linkages among land cover, discharge and total phosphorus (TP) concentrations, and loads in 25 Kansas streams. Stream monitoring locations were selected from the Kansas Department of Health and Environment stream chemistry long-term monitoring network sites at or near U.S. Geological Survey stream gauges. We linked each sample with concurrent discharge data to improve our ability to estimate TP concentrations and loads across the full range of possible flow conditions. Median TP concentration was strongly linked (R 2 = 76%) to the presence of cropland in the riparian zones of the mostly perennial streams. At baseflow, discharge data did not improve prediction of TP, but at high flows discharge was strongly linked to concentration (a threshold response occurred). Our data suggest that on average 88% of the total load occurred during the 10% of the time with the greatest discharge. Modeled reductions in peak discharges, representing increased hydrologic retention, predicted greater decreases in total annual loads than reductions of ambient concentrations because high discharge and elevated phosphorus concentrations had multiplicative effects. No measure of land use provided significant predictive power for concentrations when discharge was elevated or for concentration rise rates under increasing discharge. These results suggest that reductions of baseflow concentrations of TP in streams without wastewater dischargers may be managed by reductions of cropland uses in the riparian corridor. Additional measures may be needed to manage TP annual loads, due to the large percentage of the TP load occurring during a few high-flow events each year.</p>10aDischarge10aPerennial streams10aRiparian zones10atotal phosphorus10aWatershed management1 aBanner, E.B.K.1 aStahl, A.J.1 aDodds, W., K.  uhttps://link.springer.com/article/10.1007%2Fs00267-009-9332-6