LNWB Ch06 Soil Processes and Inputs

Overview:
Water, in its many forms is one of Whatcom County’s signature features from snow-capped mountains,to our rainy climate, salmon-bearing streams, wetlands, lakes, marine waters, and marine shorelines. Five distinct hydrologic components control the storage and movement of water through the canopy and soils: canopy interception store (green trees), upper soil zone (vadose zone, brown soil fill) store, groundwater saturated zone (gray soil fill), channel flow (blue), and artificial drainage (blue line from agriculture to channel). Surface water inputs from direct precipitation, throughfall through the vegetation canopy, and irrigation are taken as input to the unsaturated, or vadose zone soil store. The unsaturated portion of the upper soil layer (brown), or vadose zone, is shown with recharge water (blue downward line) infiltrating the surface layer of soils, draining through the unsaturated zone (brown), to recharge the saturated zone (gray). The thickness of the vadose zone changes as the water table level (hashed gray and brown interface) shifts up and down, depending on the water held in the saturated zone. Based on the input and storage in the vadose zone, recharge to groundwater (gray, saturated zone) and surface water runoff is calculated. The vadose zone soil store is decreased by artificial drainage, representing ditch and tile drains that remove water directly from the vadose zone soil store to channels. The vadose zone soil store calculation also accounts for potential upwelling from groundwater where the water table is shallow. The groundwater saturated zone calculations account for recharge, upwelling and groundwater pumping and produce baseflow as an output. In the Lower Nooksack Water Budget, baseflow is defined as the outflow from the saturated zone and referred to as groundwater contribution; and baseflow and surface runoff are combined to calculate channel flow.

Purpose:
The baseflow in streams is supported by the gradual drainage of groundwater in shallow aquifer systems. The rate of this drainage depends on the amount of water stored in shallow aquifers (depth to water table) and the hydraulic properties of the aquifer, specifically the lateral hydraulic conductivity, or its depth integral, transmissivity. The amount of water stored depends on recharge, the vertical movement of water through unsaturated soils from the surface into the shallow groundwater. The rate of recharge is determined by the supply of water above. This is a function of whether surface water input is retained in the soil zone where it is taken up by plant roots and becomes evapotranspiration, or whether it infiltrates beyond the root zone and percolates to aquifers. These processes depend on the properties of the soils, such as porosity, field capacity, and hydraulic conductivity. The representation of the hydrologic processes of recharge and drainage to baseflow on a drainage scale is done using estimates based on measured data at point locations, as well as soil texture information. As more data is collected, information about subsurface processes can be incorporated into the model representation.

For the Lower Nooksack Water Budget soils parameters, soils data was compiled from both local and federal datasets. Using data available from the Natural Resource Conversation Service (NRCS – formerly the Soil Conservation Service) soils databases (NRCS; SSURGO and STATSGO (www.soilsdatamart.gov)), we have used estimates of averaged soils parameter values over each drainage area as data inputs for the hydrology model compiled in previous work (Tarboton, 2007). These soil parameters include plant available soil moisture, soil depth, hydraulic conductivity, and wetting front suction. Earlier calibrations of Topnet-WM showed that the most sensitive and therefore important soil parameters controlling baseflow movement are saturated soil store sensitivity (f) and soil profile lateral conductivity or transmissivity (To). The Lower Nooksack transmissivity parameters were derived from aquifer hydraulic conductivity values for specific wells, completed within shallow near surface aquifers, as described in the U.S. Geological Survey (USGS) Lynden-Everson-Nooksack-Sumas (LENS) Study (Cox and Kahle, 1999). Although the variability in well data is high given the heterogeneity of glacial and alluvial deposits, interpolating available well data to derive drainage average values captures the drainage level heterogeneity. Here changes in average depth to water table described in the Department of Ecology Study, Nooksack Watershed Surficial Aquifer Characterization (Tooley and Erickson, 1996), were used. Water movement through the surficial aquifer is assumed to decrease exponentially as the depth to the water table increases based on the Topmodel algorithm (Beven, et al., 1995a).

This resource is a subset of the Lower Nooksack Water Budget (LNWB) Collection Resource.

{'Overview': '概览：水，以其多样的形态，是沃特康县（Whatcom County）的显著特征之一。从积雪覆盖的山峰，到多雨的气候，再到产鲑鱼的溪流、湿地、湖泊、海洋水域以及海岸线，水无处不在。五个独特的 hydrologic components（水文成分）控制着水通过树冠和土壤的储存与流动：树冠截留储存（绿色树木）、上层土壤区（ vadose zone，棕色土壤填充）储存、地下水饱和区（灰色土壤填充）、渠道流（蓝色）和人工排水（从农业到渠道的蓝色线条）。地表水输入，包括直接降水、通过植被冠层的透过降水以及灌溉，被视为不饱和或 vadose zone 土壤储存的输入。上层土壤层的不饱和部分（棕色），或 vadose zone，以补给水（蓝色向下线条）渗透土壤表层、通过不饱和区（棕色）排入饱和区（灰色）的方式呈现。vadose zone 土壤储存的厚度随着地下水位（灰色和棕色接口的虚线）的上下波动而变化，这取决于饱和区所含的水量。基于 vadose zone 的输入和储存，对地下水（灰色，饱和区）和地表水径流的补给进行计算。vadose zone 土壤储存的减少通过人工排水来实现，代表沟渠和排水管直接从 vadose zone 土壤储存中移除水到渠道。vadose zone 土壤储存的计算还考虑了地下水位浅时的潜在上升。地下水饱和区的计算考虑了补给、上升和地下水抽取，并产生基流作为输出。在 Lower Nooksack 水预算中，基流被定义为饱和区的流出，并被称为地下水贡献；基流和地表径流相结合以计算渠道流。

目的：河流中的基流由浅层含水层系统中地下水的缓慢排水所支持。这种排水的速度取决于浅层含水层中储存的水量（地下水位深度）和含水层的液压特性，特别是横向液压导率或其深度积分，即透水性。储存的水量取决于补给，即水从地表通过不饱和土壤的垂直运动。补给的速度由上方水的供应量决定。这是由地表水输入是否保留在土壤区，并被植物根系吸收成为蒸散作用，或者是否渗透到根系以外并渗透到含水层来决定的。这些过程依赖于土壤的特性，如孔隙率、田间持水量和液压导率。使用基于点位置测量的数据估计以及土壤质地信息，对补给和排水到基流的 hydrologic processes（水文过程）在排水尺度上的表示采用估计值。随着收集到的数据越来越多，关于地下过程的信息可以纳入模型表示。

对于 Lower Nooksack 水预算的土壤参数，从当地和联邦数据集中收集了土壤数据。利用自然资源保护服务（Natural Resource Conservation Service，简称 NRCS，原土壤保护服务）的土壤数据库（NRCS；SSURGO 和 STATSGO（www.soilsdatamart.gov））中可获得的数据，我们已经使用每个排水区域的平均土壤参数值估计作为先前工作（Tarboton，2007）中编译的 hydrology model（水文模型）的数据输入。这些土壤参数包括植物可利用土壤水分、土壤深度、液压导率和润湿前沿吸力。Topnet-WM 的早期校准表明，最敏感且因此最重要的控制基流运动的土壤参数是饱和土壤储存敏感性（f）和土壤剖面横向导率或透水性（To）。Lower Nooksack 透水性参数是从特定井的含水层液压导率值中导出的，这些井位于浅层近地表含水层中，如美国地质调查局（U.S. Geological Survey，简称 USGS）Lynden-Everson-Nooksack-Sumas（LENS）研究（Cox 和 Kahle，1999）所述。尽管由于冰川和冲积沉积物的异质性，井数据的变异性很高，但将可用的井数据插值到导出平均值以捕捉导出水平异质性。在此，根据生态部门研究《诺斯克流域地表含水层特征化》（Tooley 和 Erickson，1996），描述了地下水位平均深度的变化。假设根据 Topmodel 算法（Beven 等，1995a），随着地下水位深度的增加，地表含水层中的水流通过呈指数减少。

本资源是 Lower Nooksack 水预算（LNWB）资源子集。', 'Purpose': '目的：河流中的基流由浅层含水层系统中地下水的缓慢排水所支持。这种排水的速度取决于浅层含水层中储存的水量（地下水位深度）和含水层的液压特性，特别是横向液压导率或其深度积分，即透水性。储存的水量取决于补给，即水从地表通过不饱和土壤的垂直运动。补给的速度由上方水的供应量决定。这是由地表水输入是否保留在土壤区，并被植物根系吸收成为蒸散作用，或者是否渗透到根系以外并渗透到含水层来决定的。这些过程依赖于土壤的特性，如孔隙率、田间持水量和液压导率。使用基于点位置测量的数据估计以及土壤质地信息，对补给和排水到基流的 hydrologic processes（水文过程）在排水尺度上的表示采用估计值。随着收集到的数据越来越多，关于地下过程的信息可以纳入模型表示。

对于 Lower Nooksack 水预算的土壤参数，从当地和联邦数据集中收集了土壤数据。利用自然资源保护服务（Natural Resource Conservation Service，简称 NRCS，原土壤保护服务）的土壤数据库（NRCS；SSURGO 和 STATSGO（www.soilsdatamart.gov））中可获得的数据，我们已经使用每个排水区域的平均土壤参数值估计作为先前工作（Tarboton，2007）中编译的 hydrology model（水文模型）的数据输入。这些土壤参数包括植物可利用土壤水分、土壤深度、液压导率和润湿前沿吸力。Topnet-WM 的早期校准表明，最敏感且因此最重要的控制基流运动的土壤参数是饱和土壤储存敏感性（f）和土壤剖面横向导率或透水性（To）。Lower Nooksack 透水性参数是从特定井的含水层液压导率值中导出的，这些井位于浅层近地表含水层中，如美国地质调查局（U.S. Geological Survey，简称 USGS）Lynden-Everson-Nooksack-Sumas（LENS）研究（Cox 和 Kahle，1999）所述。尽管由于冰川和冲积沉积物的异质性，井数据的变异性很高，但将可用的井数据插值到导出平均值以捕捉导出水平异质性。在此，根据生态部门研究《诺斯克流域地表含水层特征化》（Tooley 和 Erickson，1996），描述了地下水位平均深度的变化。假设根据 Topmodel 算法（Beven 等，1995a），随着地下水位深度的增加，地表含水层中的水流通过呈指数减少。

本资源是 Lower Nooksack 水预算（LNWB）资源子集。'}