房屋的结构类型及特点.ppt

NRCS-WEPS Final Testing Report
June 28, 2007
Mike Sporcic Wind Erosion Specialist
National Technology Support Center-Central
Background
The Natural Resources Conservation Service has used the Wind Erosion Equation (WEQ) since the early 1980s. WEQ is used in two different versions: the Critical (annual) Period Method and the Management Period Method. The versions give very different answers. Management Period Method tends to have much lower erosion rates than the Critical Period Method. The model is inconsistence across state lines.
Most states east of the Mississippi River have no means of predicting wind erosion at all. This is due to very low C factors. Some of these states have wind erosion issues and require planning assistance of a prediction model.
NRCS needs a faster, robust, consistent, and more precise way to estimate wind erosion. We also need more predictive information about air quality and off site affects from saltation and surface creep.
Testing
The Agriculture Research Service Wind Erosion Research Unit (WERU) at Manhattan, KS has worked for more than 16 years to develop the Wind Erosion Prediction System. It has been designed to meet the conservation planning needs of the NRCS. An initial finished version of WEPS () was given to NRCS for testing in 2005.
NRCS accepted the model for testing on April 15, 2005. Testing of the model by NRCS was started in shortly after that time. 10 testing phases were set up by regions based on Crop Management Zones (CMZ). (See map and table on next page).
Tests have put the model into areas of the . where it will be used by NRCS. All regions are able to implement the model and calculate erosion. The following bulleted items discuss the issues encountered.
Some areas have crop growth issues especially new crops and crops that have not been run in the model before. Example: WEPS did not grow three cutting spinach winter crop correctly in NY. WEPS was not able to calculate erosion until the crop file w