development of an internet-accessible tool for the identification of hydrologically sensitive areas...

Development of an internet-accessible tool for the identification of hydrologically sensitive areas (HSA’s) and the calculation of New York State

phosphorous indicesHelen Dahlke, Daniel R. Fuka, Zachary M. Easton

Tammo S. Steenhuis

IntroductionIntroduction

• hydrologically sensitive areas (HSA‘s) are preferred flowpath in the landscapes of the humid Northeast of the US

• connect mostly agricultural land to streams and lakes

• need of estimation of the risk of nutrient loads in surface waters: CNMP planner help producer to identify high risk transport areas when applying manure

• current tools use a fixed distance setting from a watercourse and/or soil wetness indicators

• need of tools that consider the landscape position of saturation areas and their spatial-temporal dynamics

• tool must be user-friendly and easy accessible

study areasstudy areas Salmon Creek: 227 km² (87.7 mi²)

Fall Creek: 326 km² (126 mi²)

Six Mile Creek: 102 km² (39 mi²)

model approachmodel approach

rainfall ETIf rainfall > ET,

soil wets upIf rainfall > soil storage,

excess overland flow

• flowaccumulation• slope• soil depth• soil hydraulic

conductivity

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Soil topographic wetness index

• Calculation of the fractional area of the watershed prone to saturation

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Google Earth-based HSA-toolGoogle Earth-based HSA-tool

• Google Earth (http://earth.google.com) is free software that provides a virtual globe program

• it maps earth by superimposition of satellite images, aerial phorographs and GIS maps over a 3D globe

• user can program their own data overlays of vector or raster data using the Keyhole Markup Language (KML)

• maps can be animated based on a time stemp ideal for time series application such as simple hydrological models

realization of the HSA-tool in Google Earthrealization of the HSA-tool in Google Earth

Soil topographic wetness index [Geo-Tiff]

Soil topographic wetness index [GRID]

• reclassification into 255 classes of equal area• export into Geo-Tiff

HSAimage [png]

modelled fractional area of HSA‘s [table]

• conversion to web-image

*.png file• 1% incremental area

images KML-file for Google Earth

realization of the HSA-tool in Google Earthrealization of the HSA-tool in Google Earthcontrol bar for timeseries simulation

loaded images of HSA‘s for each day of simulation

Six Mile Creek

realization of the HSA-tool in Google Earthrealization of the HSA-tool in Google Earth

daily estimated level of phosphorous load is displayd at the outlet of the catchment

http://vsa-hydro.cornell.drfuka.org/townbrook/1998.kml

http://vsa-hydro.cornell.drfuka.org/sixmile/1998-05.kml

http://128.253.239.23/Website/Imagetest/viewer.htm