LNWB Ch09 Artificial Drainage - watershed and wet nonhydric minus tiles shape files

Compressed GIS files used in PhaseIIITask4 to create ditch and tile drain layers.

Spatial data files specifying the areas with ditch and tile drainage were developed in 2004 by the USDA, Natural Resources Conservation Service (NRCS; Resource Conservationist, John Gillies, and Agricultural Engineer, Dean Renner). Drainage coefficients from NRCS technical guides are shown in Table 2. The drained areas were estimated using a geographic information system (GIS) to identify hydric soils on agricultural land use areas, based on the assumption that if a hydric soil was cleared and in agricultural use, then there was a drainage system in place to manage water using sub-surface (tile) and surface (open ditch) practices. For the Lower Nooksack Water Budget these are areas used to determine the tile drained and ditch drained fraction of each drainage model element as well as to assign drainage coefficients.

This resource is a subset of the LNWB Ch09 Artificial Drainage Collection Resource.

用于第三阶段任务4创建排水沟和砖瓦排水层的数据压缩GIS文件。由美国农业部自然资源保护服务局（NRCS；资源保护专家约翰·吉利斯和农业工程师迪恩·雷纳）于2004年开发，以指定具有排水沟和砖瓦排水的区域。表2展示了NRCS技术指南中的排水系数。通过地理信息系统（GIS）估计了排水区域，该系统基于以下假设：如果水田土壤被清理并用于农业，则已存在一套排水系统，通过地下（砖瓦）和地表（开放式排水沟）的方法来管理水分。对于Lower Nooksack水资源预算，这些区域用于确定每个排水模型元素的砖瓦排水和排水沟排水比例，以及分配排水系数。本资源是LNWB Ch09人工排水收集资源的子集。