5 david bosch 2017 bosch lrw svi
•Als PPTX, PDF herunterladen•
1 gefällt mir•221 views
72nd SWCS International Annual Conference July 30-August 2, 2017 Madison, WI
Empfohlen
Empfohlen
Weitere ähnliche Inhalte
Ähnlich wie 5 david bosch 2017 bosch lrw svi
Ähnlich wie 5 david bosch 2017 bosch lrw svi (7)
Mehr von Soil and Water Conservation Society
Mehr von Soil and Water Conservation Society (20)
Kürzlich hochgeladen
Kürzlich hochgeladen (20)
5 david bosch 2017 bosch lrw svi
- 1. Soil Vulnerability Index assessment in Little River Experimental Watershed, Georgia David Bosch, USDA-ARS, Southeast Watershed Research Lab, Tifton, GA Sapana Lohani, Claire Baffaut, and Allen Thompson
- 2. Little River Watershed, Georgia • 334 km2 • broad floodplains • mostly sandy soils • most slopes are less than 5%, with some valley side slopes ranging from 5-15% • very little (insignificant) artificial drainage
- 3. Hydrologic soil groups HSG Percent Area A 7.4 B 57.9 C 26.2 D 8.4
- 4. Slopes Slope Category (%) % Area 10-m DEM % Area 30-m DEM 0-2 33.0 34.9 2-4 40.5 42.4 4-6 19.2 18.6 >6 7.3 4.1
- 5. Soil Runoff Potential SVI Runoff Classes Percent Area Low 63 Moderate 27 Moderately High 3 High 7
- 6. Soil Runoff Potential • High slope areas predominantly at upland field / riparian buffer interface. • Typically forested areas, not row crops.
- 7. Soil Leaching Potential Leaching Index Percent Area Low 8 Moderate 27 Moderately High 26 High 39
- 8. Summary – Runoff Potential • SVI runoff potential useful for identifying areas of inherently high runoff in LRW. • Could be improved by incorporating slope length. • Could be refined by introducing land cover and areal extent.
- 9. Summary – Leaching Potential • SVI leaching potential useful for identifying areas with inherently high leaching in LRW. • Could be improved by introducing other controlling features such as groundwater. • Could be refined by introducing land cover and areal extent. • Although leaching potential may be a good indicator of field level leaching, it may not necessarily be a good indicator of watershed water quality.
- 10. SEWRU Thank You for Your Attention!
- 12. LREW Conservation Practices • USDA-NRCS recommended conservation programs have been implemented on nearly 20% of the LRW land area in the last 30 years • Forty-seven different conservation practices • nutrient management (13.1%) • pest management (12.9%) • grassed waterways (9.6%) • contour farming (9.5%) • seasonal residue management (8.9%) • terraces (8.8%)
Hinweis der Redaktion
- Key characteristics; broad floodplains, sandy soils, low slopes, groundwater controlled
- Predominantly hydrologic soil groups B and C (84%), most with slopes < 5%, small percentage with high erodibility (K>=0.28). Hydrologic group D soils (8%) are mostly low slopes (0-2%). Most agronomic soils are in the B and C groups. Sandy soils which promote leaching.
- Predominantly low slopes, 74% of land area has < 4% slope, with 33% <2% slope. High slopes (>6%) are primarily of short slope length, not typical. Slopes <=3 fairly common, important for leaching potential. Higher resolution DEM picks up smaller areas of higher slopes, greater slope %.
- Areas of high runoff potential are located along the streams (C soils with high slopes (>6%) and relatively short slope length) while moderately high runoff potential can be located in the uplands (isolated hydrologic soil group C soils with moderate slopes). Largely tied to slope for LRW (predominantly B and C soils)
- Areas of high runoff potential are located along the streams (C soils with high slopes (>6%) and relatively short slope length) while moderately high runoff potential can be located in the uplands (isolated hydrologic soil group C soils with moderate slopes). Largely tied to slope for LRW (predominantly B and C soils)
- 65 % of the area has high and moderately high leaching potential (sandy soils); Hydrologic soil group B soils with slope <3% and K<0.24, dominant soil, Tifton, would fall in this category. Also a large fraction of sands in the floodplain fall into high risk class, hydrologic soil group A (not farmed), leaching controlled by groundwater. Tied to slope and hydrologic soil group.
- Some land area could have more than one practice.
- Little overlap between areas with high runoff potential and implemented practices. No more likely to implement practices on high runoff potential areas.
- Higher overlap between areas with high leaching potential and implemented practices, but equally high overlap with areas that do not have any practices. Proportion of high risk areas with practices to the total high risk area is the same as the proportion of area with practices to total cropped area.