Baseflow contribution to nitrates in an urban stream in Daejeon, Korea

Abstract

It is a well-known fact that baseflow discharge of rainfall runoff significantly impacts the quality of surface water. In this paper, the impact of nitrates discharged as baseflow on stream water quality were studied using PULSE, a hydrograph separation software developed by USGS, to calculate the monthly baseflow discharge. We took water quality and flow rate data from a monitoring station site (code: Ghapcehon2) in Daejeon city and acquired 2005 groundwater quality data in the watershed from government agencies. Agricultural and forestry land use are dominant in the area. The baseflow contributes 85%-95% of stream flows during the spring and fall, 25%-38% during the summer and winter. The monthly nitrate loading discharged as baseflow for Ghapcheon2 was estimated by using monitored nitrate concentrations of groundwater in the watershed. Nitrate loading induced by baseflow at Ghapcheon2 was estimated as 5.4 tons of NO3(-)-N/km(2), which is about 60% of nitrate loading of surface water, or 9.2 tons of NO3(-)-N/km(2). This study shows that groundwater quality monitoring is important for proper management of surface water quality.

Annual nitrate load patterns in an agricultural watershed in consecutive dry years

“…The BER in this study area was relatively higher than that in other agricultural watersheds. For example, the BER in the Raccoon River Watershed, USA, ranged from 0.23 to 1.61 and averaged 1.23 (Schilling & Zhang 2004); the BER in the Daejeon region, South Korea, ranged from 0.6 to 1.5 (Kim et al 2010). These results suggest that controlling the baseflow NO 3 -N concentration plays a key role in NPS NO 3 -N management of the upper and middle HRB.…”

Baseflow Recession Analysis for Flood‐Prone Black Sea Watersheds in Turkey

“…A better understanding of baseflow can help in detecting irrigation withdrawals during low flow periods, making water supply estimates and forecasts, hydropower, water quality applications, determining storage requirements for maintenance of adequate flow for wastewater dilution, and understanding the dynamics of nitrate fluxes from aquifer storages and agricultural systems and to urban streams . The uncertainty of baseflow prediction is quiet large , and it is not yet feasible in practice to measure baseflow in the field.…”