Background Why this tool? Why open source? What does OpenNSPECT do? What do you need to run it? What does it produce? Who else has used it? How can you get involved?
Why this tool? Hawai‘i managers needed a simple, quick screening tool –Usable in a public setting –Could run on a laptop Initially applied in Wai‘anae region in O‘ahu, Hawai‘i –Pressure from residential development –Sensitive coastal habitats 2004: Esri ArcGIS 8.x extension –Updated for 9.0, 9.1, 9.2, : OpenNSPECT
Open Source and ESRI versions Strengths –Speed –“Free” –Community support Weaknesses –Different program learning curve, anxiety, distrust –Some features missing –Community support
What does OpenNSPECT do? Water quality screening tool Spatially distributed (raster-based) pollutant and sediment yield model Compares the effects of different land cover and land use scenarios on total yields User friendly graphical interface within a GIS environment
Processes Simulated Topography determines flow direction and slope Soil characteristics, land cover, and precipitation determine runoff Runoff, land cover, and pollutant coefficients determine pollutant loads Runoff, topography, soil characteristics, and land cover determine sediment loads
Uses Existing Approaches Rainfall runoff –Soil Conservation Service (SCS) curve number technique Nonpoint pollutant –Event mean concentration technique Sediment erosion –Universal Soil Loss Equation (USLE) Modified (MUSLE) Revised (RUSLE)
Assumptions/Limitations Omitted processes – Stormwater drainage – Stream diversions – Snowmelt – Landslides No time component for – Runoff dynamics – Sediment redeposition – Pollutant dynamics Source: NASA Earth Science Enterprise
What do you need to run it? National sources* –Land cover data –Topography –Precipitation –Soils data –Pollutant coefficients –Rainfall erosivity Local sources –Water quality standards –Additional pollutant coefficients *Local “tuning” improves accuracy
Topography Defines flow direction, stream networks, watersheds Default –U.S. Geological Survey (USGS) 30 m resolution digital elevation model Resolution impacts processing speed and file size
Land Cover Foundation for runoff quantity, sediment yield, pollutant yield Default –Coastal Change Analysis Program (C-CAP) –30 m resolution Flexible –Can easily substitute any land cover grid
Soils Runoff and erosion estimates are dependent upon soils and land cover Default –SSURGO soils † –County level resolution Infiltration rate –Hydrologic group Soil erodibility –K-factor † Soil Survey Geographic Database provided by the Natural Resources Conservation Service
Precipitation Derived from point estimates or modeled –OSU PRISM data Annual average Single event rainfall
Basic Analysis Baseline analyses –Objective Run a basic analysis with OpenNSPECT and produce baseline runoff, erosion, and pollutant load data sets for an annual time scale. –Important Learning Objectives: Gain familiarity with the OpenNSPECT user interface. Learn which data sets are necessary to run the model. Understand the properties associated with the Pollutants tab. Understand the properties associated with the Erosion tab. Understand the function of the Local Effects Only option. Learn to visually assess the data output.
Exercise 1 Baseline analysis (accumulated effects) –Accumulated runoff, nonpoint source pollutants, and eroded sediments are estimated. –Accumulated effects include: Expected pollutant or sediment concentration at a cell. Contributions from upstream cells. Page 3
Exercise 2 Baseline analysis (local effects) –Local effects of runoff, nonpoint source pollution, and erosion are estimated. –Local effects include expected pollutant or sediment concentration at a cell without upslope contributions. Page 5
Exercises 1 and 2 Results Baseline runoff, sediment loads, and nitrogen concentrations (accumulated and nonaccumulated) –Model outputs are representative of the landscape conditions during the time at which the input data was collected. Visual interpretation –Topography was associated with the shape and density of drainage networks. –Land cover types were associated with various degrees of sediment and pollutant loads.
Exercise 1 Results
Exercise 2 Results
Outline Background Getting started Basic analysis Advanced analysis –Management scenario Exercise 3 – Accumulated and Local effects –Alternative land use Exercise 4 - Accumulated effects
Advanced Analysis Management scenario analyses –Objective Run an analysis that incorporates a hypothetical management scenario and examines the potential changes to runoff, erosion, and pollution. –Important Learning Objectives: Understand the properties associated with the Management Scenarios tab. Learn to incorporate a management scenario. Learn to quantitatively evaluate the data output. Understand the relative contributions of different land cover classes to nonpoint source pollution.
Exercises 3 Management scenario –Integration of a hypothetical land management scenario Grassland and scrub/shrub converted to low intensity developed land. –Local effects of runoff, nonpoint-source pollution, and erosion are estimated. –Accumulated effects of runoff, nonpoint-source pollution, and erosion are estimated. –Comparison to baseline results. Page 7
Exercise 3 Results Nitrogen yields (mg) A.Baseline conditions B.Low density residential management scenario C.Difference between A and B –The 0.2 km 2 development is predicted to yield an additional 86.7 kilograms of nitrogen under the alternative land management scenario (a 138 percent increase). Baseline Management Comparison % Change
Exercise 3 Results Nitrogen yields (mg) –This translates to a 0.5 percent increase in the accumulated nitrogen load for the entire 14.1 km 2 watershed.
Advanced Analysis Alternative land use scenario analysis –Objective Run an analysis with a new land use scenario and produce modified runoff, erosion, and pollutant load data sets for an annual timescale. –Important learning objectives: Understand the properties associated with the Land Use tab. Learn to parameterize a new land use scenario. Learn to quantitatively evaluate the data output.
Exercise 4 Alternative land use scenario (accumulated effects) –Integration of a hypothetical land use scenario New pollutant coefficients defined for a golf course. –Accumulated effects of runoff, nonpoint source pollution, and erosion are estimated. –Comparison to baseline results. Page 11
Exercise 4 Results Net decrease in accumulated nitrogen load –Land cover beneath the golf course polygon was recoded. –SCS curve numbers control runoff volume. –Runoff volume controls pollutant load.
Questions? Download OpenNSPECT: Today’s Trainer: Dave Eslinger Project Contacts: Dave Eslinger, Project lead Shan Burkhalter Matt Pendleton