Mean annual water-budget components for the Island of Oahu, Hawaii, for current conditions, 2001-10 rainfall and 2001-10 land cover (version 2.0)

The shapefile associated with this metadata file represents the spatial distribution of mean annual water-budget components, in inches, for the Island of Oahu, Hawaii. The water-budget components in the shapefile were computed by a water-budget model for a scenario representative of current conditions (2001-10 rainfall and 2001-10 land cover), as described in USGS Scientific Investigations Report (USGS SIR) 2015-5164. The model was developed for estimating groundwater recharge and other water-budget components for each subarea of the model. The model-subarea dataset, consisting of 395,955 subareas (polygons), was generated using Esri ArcGIS software by intersecting (merging) multiple spatial datasets. Spatial datasets merged includes those that characterize the spatial distribution of hydrologic and physical conditions (rainfall, fog interception, irrigation, reference evapotranspiration, direct runoff, soil type, and land cover) that the model uses to compute groundwater recharge and other water-budget components. Additional spatial datasets merged into the model-subarea dataset include those of select geographic features that assist in analyzing model results. This metadata file describes the process of merging these spatial datasets. The shapefile attribute information associated with each polygon present an estimate of mean annual rainfall, fog interception, irrigation, septic-system leachate, runoff, canopy evaporation, actual evapotranspiration, storm-drain capture, net precipitation, total evapotranspiration, recharge, and seepage from water main, reservoirs, and cesspools. This shapefile also includes select geographic and land-cover attributes of the polygons. Brief descriptions of the water-budget components and attributes are included in this metadata file. Refer to USGS SIR 2015-5164 and SIR 2015-5010 for further details of the methods and sources used to determine these components and attributes.

本元数据文件关联的形状文件（shapefile）展示了夏威夷瓦胡岛多年平均水量平衡各分量的空间分布，单位为英寸。该形状文件中的水量平衡分量由水量平衡模型计算得到，对应代表当前条件的情景（2001-2010年降雨数据与2001-2010年土地覆被数据），相关说明详见美国地质调查局（USGS）科学调查报告（SIR）2015-5164。该模型专为估算模型各子区域的地下水补给量及其他水量平衡分量而开发。该模型子区域数据集包含395955个子区域（多边形），通过Esri ArcGIS软件对多份空间数据集进行相交（合并）操作生成。本次合并的空间数据集涵盖了模型用于计算地下水补给量及其他水量平衡分量的水文与物理条件空间分布数据，包括降雨、雾截留、灌溉、参考蒸散、直接径流、土壤类型及土地覆被等数据。此外，合并至模型子区域数据集的空间数据集还包含若干精选地理特征数据，用于辅助模型结果分析。本元数据文件即对上述空间数据集的合并流程予以说明。各多边形对应的形状文件属性信息，包含了多年平均降雨、雾截留、灌溉、化粪池渗滤液、径流、冠层蒸发、实际蒸散、雨水管网收集量、净降水量、总蒸散、补给量以及供水管道、水库与渗坑的渗漏量等估算值。该形状文件还包含各多边形的精选地理与土地覆被属性数据。本元数据文件中还附带了水量平衡分量与属性数据的简要说明。如需了解上述分量与属性的确定方法及数据来源的更多细节，请参阅USGS SIR 2015-5164与SIR 2015-5010。