Potentiometric surface - simulated 1970 raster

## **Abstract** \n\nThis dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied. \n\n \n\nThe simulated 1970 unconfined potentiometric surface (watertable) across the entire model domain. The potentiometric surface represents the uppermost saturated surface and variability over the region. \n\n \n\nChoosing a year that best represents the climatic circumstances for the simulation objectives is an essential part of the steady-state assessment. This decision was influenced by the availability of appropriate calibration data. This approach generally allows for the selection of a year that was outside the bounds of a longer term shift in annual rainfall distribution. The selected steady-state condition was based on 1970 rainfall and assumed no groundwater extractions. This initial state was selected to represent predevelopment conditions as post-1970 historic groundwater pumping in the region (on and offshore) have not achieved a quasi-equilibrium response as based on available groundwater hydrograph trends. The transient simulation period was 1970 to 2012. This period captures both pre-mine development and a range of varying climatic conditions including above average wet and dry sequences. The 1970 starting date enables the incorporation of historic groundwater extraction data into the model and provides sufficient lead time for the groundwater model to minimise the impact of initial conditions on model predictions associated with the period of interest namely the calibration/validation period of 2000 to 2012. Copied from the Gippsland Groundwater Model report 2015.\n\n## **Purpose** \n\nThe surface indicates the likely regional groundwater flow direction and gradient in the area illustrating the condition at time point 1970.\n\n## **Dataset History** \n\nThe simulated 1970 unconfined potentiometric surface (watertable) and depth-to-watertable across the entire model domain is shown in Figure 114 and Figure 115 respectively. (ED. see figures in the Gippsland Groundwater model report). Visual comparison of the Victorian SAFE depth to watertable map (Figure 116) with the steady-state simulated depth to watertable shows the watertable surface is reasonable within the alluvial systems however in some upland locations the watertable appears in greater connection with surface features than presented in the Victorian Aquifer Framework (VAF) data. This is not considered a significant issue as these areas are well beyond the zone of interest. It must be noted that the VAF depth to watertable map was derived using a combination of terrain analysis and interpolated bore data and in part on proximity to streams within the exposed basement areas. Additionally the VAF reflects the 1990 conditions whereas the simulated steady-state depth to watertable represents pre-development conditions. As such it is expected that that the simulated steady-state depth to watertable map would have a greater area of shallow watertable than reported in the VAF spatial layer. \n\n\n\nThis text copied from the Gippsland Groundwater Model report 2015. See Beverly et al (2015) for more details.\n\n## **Dataset Citation** \n\nBioregional Assessment Programme (2015) Potentiometric surface - simulated 1970 raster. Bioregional Assessment Source Dataset. Viewed 05 October 2018, http://data.bioregionalassessments.gov.au/dataset/883f86cd-8d1c-4672-bcde-7b872248ddb2.

## **摘要**

本数据集及其元数据声明由第三方提供给生物区域评估计划（Bioregional Assessment Programme），并按原始提供形式呈现于此。

1970年整个模型域内的非承压水位面（potentiometric surface，潜水面）模拟结果。水位面代表区域内最上层的饱和面及其空间变异性。

选择最能体现模拟目标气候条件的年份是稳态评估的关键环节。这一决策受限于可用校准数据的情况。该方法通常可选择超出年降雨量分布长期变化范围的年份。所选稳态条件基于1970年降雨量，并假设无地下水抽取。由于1970年后该区域（陆上及海上）的历史地下水开采未达到准平衡状态（依据现有地下水水位动态曲线趋势），因此选择此初始状态以代表开发前条件。瞬态模拟时段为1970年至2012年，该时段涵盖了矿山开发前阶段及多种气候条件（包括高于平均水平的干湿序列）。1970年的起始日期可将历史地下水开采数据纳入模型，并为地下水模型提供充足的准备时间，以最小化初始条件对目标时段（即2000-2012年校准/验证期）模型预测结果的影响。内容复制自2015年吉普斯兰地下水模型报告。

## **目的**

该水位面反映了1970年研究区可能的区域地下水流向及水力梯度。

## **数据集历史**

1970年整个模型域内的非承压水位面（potentiometric surface，潜水面）模拟结果及潜水面埋深（depth-to-watertable）分别见图114和图115（编者注：详见吉普斯兰地下水模型报告中的图表）。将维多利亚州SAFE潜水面埋深图（图116）与稳态模拟的潜水面埋深进行可视化对比发现：冲积系统内的潜水面模拟结果合理，但在部分高地地区，潜水面与地表特征的关联性似乎比维多利亚州含水层框架（Victorian Aquifer Framework, VAF）数据所呈现的更强。由于这些区域远超出关注范围，因此不被视为重大问题。需注意的是，VAF潜水面埋深图是结合地形分析、插值钻孔数据及裸露基岩区溪流邻近度信息生成的。此外，VAF反映的是1990年的条件，而模拟的稳态潜水面埋深代表开发前状态。因此，预期模拟的稳态潜水面埋深图中浅层潜水面的面积将大于VAF空间图层所报告的面积。

本文本复制自2015年吉普斯兰地下水模型报告。详情请参见Beverly等人（2015）的研究。

## **数据集引用**

生物区域评估计划（2015）. 1970年水位面（potentiometric surface）模拟栅格数据. 生物区域评估源数据集. 查阅日期：2018年10月5日，http://data.bioregionalassessments.gov.au/dataset/883f86cd-8d1c-4672-bcde-7b872248ddb2.