HARLS - CS: Applications

Faculty: Chaubey

Three ongoing research projects funded by USDA/EPA to assess land use impacts on water quality in Beaver Lake, Eucha Lake, and Lincoln Lake are significantly enhanced by acquisition of the HARLS-CS. Dr. Chaubey and his colleagues have been actively involved in water quality management in multiuse watersheds for point/non-point source pollution. Currently available water quality models require accurate and detailed measurement data for calibration and watershed response prediction. One of the challenges of watershed/water quality management is rapid acquisition of detailed water quality data. Although remote sensing of water quality parameters using satellites offers a significant improvement in this direction, the biggest constraint is scheduling of water quality monitoring that coincides with satellite schedules. The availability of the HARLS-CS enables us to collect high resolution data under conditions when satellite data cannot be obtained (e.g., cloudy days) and at times when satellites paths are not over the study area. This enables us to better understand water quality processes and to improve water quality models significantly.

Dr. Chaubey's research efforts are also focused on understanding runoff processes in the landscape. Even though the dynamic nature of surface runoff generation during storm events has been recognized for quite some time, very little data currently exist quantifying spatial distribution of runoff-contributing areas (also called runoff-source areas) in a watershed (Wood et al. 1990). Runoff generation is a highly nonlinear and spatially variable process involving both surface and subsurface pathways (Hoover 1990) over often small and identifiable portions of a landscape (e.g., Gburek and Sharpley 1998). Freeze (1974) reported that storm hydrographs originate from small but consistent portions of upstream areas that constitute less than 10% (usually 1-3%) of the watershed area, and even on these areas, only 10-30% of the rainfall causes overland flow. Yet current management practices treat an entire field as one homogeneous unit for nutrient management plan development (Pionke et al.1997). Many hydrologic models continue to be based on a point-scale model of watershed response, with the only recognition of spatial variability being a multiplication by the contributing watershed area (Wood et al. 1990). Given that runoff is the primary mechanism of sediment and soluble nutrient transport (such as nitrogen, N and phosphorus, P), identification of runoff-contributing areas is, therefore, very critical for effectively managing water resource integrity. The rainfall intensity and duration, antecedent soil moisture conditions, soils, topography, and groundwater levels control the extent of these runoff-contributing areas in a watershed (Wolock 1993; Wood et al. 1990). There is a need to quantify the interactions among field characteristics (soils, land use, topography) and hydrologically active areas that contribute to surface runoff. Identification and quantification of runoff-contributing areas have implications for a wide range of hydrologic/water quality problems, including management of runoff transport of nonpoint source pollutants and understanding differences in the response of catchments within the same geographical region.

The HARLS-CS enhances the competitiveness in acquiring research funding from federal/state agencies and will directly enable Dr. Chaubey to answer the following research questions: (1) Can we identify critical runoff-contributing areas in watersheds of the Ozark Highlands? (2) What linkages exist between the runoff-contributing areas, rainfall patterns, and watershed characteristics in this region? (3) How are runoff-contributing areas related to nutrient transport (especially P which is the nutrient of concern in this region) at various spatial scales and how it can be used to develop/improve source and transport component of nutrients in currently available models (e.g., P-Index) for watershed management?