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Role Of Spatial Scale In Sub-Area Prioritization To Reduce Impact Of Planned Land Use/Cover Alternations Of Watershed Responses
Citation:
KALIN, L. AND M. M. HANTUSH. Role Of Spatial Scale In Sub-Area Prioritization To Reduce Impact Of Planned Land Use/Cover Alternations Of Watershed Responses. Presented at Emerging Issues Along Urban/Rural Interfaces, Atlanta, GA, April 09 - 12, 2007.
Impact/Purpose:
An index based method was developed and applied to the rapidly urbanizing Pocono Creek Water watershed in Eastern Pennsylvania to prioritize portions of the watershed based on their contributions to the increase/decline of the flow characteristics of interest (annual maximum daily flow, 7-day average low-flow having 10 year return period, 7Q10, and monthly median of daily flow) at the main outlet by dividing the watershed into smaller units. This paper extends the work to address two issues likely to play key roles on the ranking of high impact areas: i) level of discretization (spatial resolution), and ii) configuration of the point of consideration, i.e. location where the water quality/quantity criteria is implemented.
Description:
An index based methodology is presented that rank the sub-areas in a watershed based on their relative impacts on watershed response to anticipated land developments. We argue in this paper that the spatial locations of such critical areas are dependent on the extent of watershed subdivision. In other words, a high-impact-area could be overlooked if the watershed is not partitioned into small enough management units. The hypothesis is tested on the 98.8 km2 Pocono Creek watershed in Eastern Pennsylvania, which is threatened by rapid population growth and urbanization. The watershed was divided into 29 subwatersheds and by aggregating them 7 management areas are formed, referred to as finer and coarser resolutions, respectively. Analysis showed that some of the highly ranked subwatersheds are found to fall in moderately to lowly ranked management areas. It was further shown that subwatershed rankings vary slightly with the location where water quality/quantity criteria is implemented. It is also found that rankings of subwatersheds upstream from the point of interest, at the main outlet or any interior point in the watershed, may be influenced by the time scale of the hydrologic processes.