GroMoPo Metadata for Ravenna saltwater intrusion model

The Ravenna pine forests represent an historical landmark in the Po River Plain. They have great environmental, historical and tourist value. The San Vitale pine forest is located 10 km north of the town. It is surrounded by an urban area, the city industrial infrastructure and the waterworks of the agricultural drainage system. Most land in this area is below mean sea level. As a result, no natural freshwater hydraulic gradient contrasts the density gradient of saltwater. In the last century, many events (land subsidence; land reclamation and drainage; urban and industrial development and gas and deep groundwater extractions; coastal dune destruction) led to the intrusion of large volumes of brackish and saline groundwater. Today the freshwater in this coastal aquifer consists of low salinity water tenses floating on the saltwater wedge. This study is aimed at understanding how past and present human activities have affected the saltwater intrusion process in the phreatic aquifer and how the predicted future sea level rise will affect the salinisation process. We used a numerical model to quantify these effects on the density-dependent groundwater flow, hydraulic head and salinity distribution, seepage and salt load fluxes to the surface water system. The simulations show that over the last century artificial subsidence and heavy drainage started the salinisation process in the study area and a relative sea level rise will accelerate the increase in salt toad in the coming decades, affecting the entire aquifer. Climatic conditions in the area result in limited precipitations throughout the year and preclude efficient aquifer recharge, especially in spring and summer when saltwater seepage is extensive. The lack of a continuous coastal dune system favors salt wedge intrusion. (c) 2007 Elsevier B.V. All rights reserved.拉文纳松树林是波河平原上的历史地标，兼具卓越的环境、历史与旅游价值。 圣维塔莱松树林位于该镇以北10公里处，被城区、城市工业基础设施及农业排水系统的水利设施环绕。该区域多数陆地低于平均海平面，因此缺乏能够抵消咸水密度梯度的天然淡水水力梯度。 上个世纪，地面沉降、土地开垦与排水、城市与工业发展、天然气及深层地下水开采、海岸沙丘破坏等诸多人类活动，导致大量半咸地下水（brackish groundwater）与咸地下水入侵该区域。如今，该海岸含水层（coastal aquifer）中的淡水为低盐度水透镜，漂浮于咸水楔（saltwater wedge）之上。 本研究旨在厘清过去与当前人类活动如何影响潜水含水层（phreatic aquifer）中的咸水入侵过程，以及未来预计的海平面上升将如何作用于盐渍化进程。 我们采用数值模型，量化了上述因素对密度依赖型地下水流（density-dependent groundwater flow）、水头（hydraulic head）与盐度分布、渗流以及向地表水系统输送的盐负荷通量（salt load fluxes）的影响。 模拟结果表明，上个世纪的人工沉降与高强度排水启动了研究区域的盐渍化进程；未来数十年内，相对海平面上升将加速盐负荷的增长，进而波及整个含水层。 该区域气候条件导致全年降水稀少，难以实现有效的含水层补给，尤其在咸水渗流范围广泛的春夏两季。缺乏连续的海岸沙丘系统，进一步加剧了咸水楔的入侵。 ©2007 Elsevier B.V. 保留所有权利。