1. The Need for High Resolution Digital Elevation Data for Precision Conservation in Minnesota Dr. David Mulla Professor and W.E. Larson Chair for Soil and Water Resources Department of Soil, Water, & Climate University of Minnesota
4. Precision Conservation Example Source: Sharpley et al. 2006. Nutrient Management Practices. In Environmental Benefits of Conservation on Cropland: The Status of Our Knowledge. Schnepf and Cox (eds). Soil and Water Conservation Society, Ankeny Iowa.
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6. Precision Conservation Example Sites of Biodiversity Significance Wildlife Management Areas 250m buffer around current WMAs and Biodiversity Sites
Agriculture or cultivated lands are sources of sediment and nutrients Hay, pasture, grassland, forest and lakes are minor contributors to this issue. Bogs and forested wetlands are sources of tannic acid. Urban areas provide sediment particles, and nutrients.
The full spectrum of human activities on the land: conservancy and restoration activity low impact design in urban and shoreland development and redevelopment BMPs in agriculture and other land use Besides cost benefit, need critical evaluation of opportunities and benefits of improved regulation of major land altering uses and activities Value - Information needs to be distilled, synthesized and make accessible and understandable to users The potential to reduce the adverse effects of land use practices is significant
These primary terrain attributes are the basis for terrain indices employed throughout this analysis. (Here slope is presented in percent but in subsequent calculations, this value was divided by 100 to equate to the tangent of slope angle. To avoid data errors in secondary attribute calculation, slope values of 0 were reclassified to 0.001. ) Specific catchment area, also known as contributing area or flow accumulation, represents the total upslope land area that drains into any single cell. SCA was calculated based on the D∞ algorithm of flow routing (Tarboton, 1997).
The compound topographic index, also known as the topographic wetness index, is a secondary terrain attribute which identifies areas on the landscape with a potential for ponding or saturation.
Stream Power Index is a secondary terrain attribute that measures the erosive power of flowing water. Stream power itself is a misnomer; this index does not quantify the power of streams, but the power of overland flow.
Construction site runoff
This layer was created using a threshold of greater than 11.5 applied to smoothed CTI values and the condition of “poorly drained” or “very poorly drained” soils, based on SSURGO soils data.
When present in an agricultural field, these depressional features are typically dealt with by installing open surface inlets that route water underground to subsurface drain tiles. Prior to agricultural drainage, these topographic features held water, which reduced peak flows due to temporary storage and evapotranspiration. These features also improved the quality of water by removing sediments and NO3. Open surface inlets increase the volume of water generated from the landscape and also decrease the natural ability of these landscape features to improve water quality. These areas could benefit by replacing drain inlets with rock inlets or French drains that regulate water flows and filter sediments (ag production = cultivated land/pasture in the 2001 National Land Cover Dataset)
Here is an example of such features on the landscape. Notice (in the photos) how the critical area on the left identifies an active wetland and it’s drainage inlet. The critical area on the right identifies an agricultural field that likely contributes a lot of subsurface drainage during storm events. This layer is also useful for a rapid method of identifying wetland restoration sites.
Riparian critical areas can be used to locate probable transport pathways for contaminants during periods of heavy rainfall or peak flows. These features are often found near streams, but the term riparian does not imply these features are only limited to stream/landscape interfaces. These features would benefit from conservation efforts such as vegetative buffers or when present in an agricultural field, they may be sites well suited for becoming grassed waterways
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