Universidad Autónoma de Baja California, Instituto de Investigaciones Oceanológicas, Carretera Transpeninsular Ensenada-Tijuana, N° 3917, Fraccionamiento Playitas, C.P. 22860 Ensenada, Baja California, Mexico.
Universidad Autónoma de Baja California, Instituto de Investigaciones Oceanológicas, Carretera Transpeninsular Ensenada-Tijuana, N° 3917, Fraccionamiento Playitas, C.P. 22860 Ensenada, Baja California, Mexico.
Sci Total Environ. 2020 Apr 15;713:136715. doi: 10.1016/j.scitotenv.2020.136715. Epub 2020 Jan 15.
Rapid depletion of aquifers in semiarid and arid regions threatens water security. This holds true especially in emerging countries where insufficient knowledge about aquifer systems precludes the implementation of advanced management measures, such as managed aquifer recharge. This study deals with the generation of baseline knowledge for the assessment of aquifers in arid and semiarid regions where artificial recharge with reclaimed water gains increasing impetus. The Guadalupe aquifer in Baja California provides water to 57% of the Mexican wine industry. Recent plans foresee a partial replenishment of its depleted groundwater reserves by transferring treated waste water from the Mexico-USA border for irrigation. The aquifer demonstrated to have a rapid response by rising the water table of about +20 m in relation to natural recharge under an intense rainfall period of 236 mm. Two predominant recharge sources were identified based on a geochemical multi-tracer approach: (a) water of modern age (<5 yr, >1.8 TU) and mixed water of recent-submodern age (H 0.8-1.8 TU), and (b) sub-modern waters that were recharged before 1952 (H < 0.5 TU). Water of the first type originate in the main Guadalupe stream, which has a more depleted average δO isotope value (-7.8‰) than average local rainwater (-2.0‰). The stream water initially has a Na-HCO composition and recharges the entire Calafia zone and most groundwater along the riverbed across the valley. Water of the second type is mostly derived from hill-slope groundwater that has a stable isotope composition of mixed local rainwater and a NaCl composition. High total dissolved solids >2 g l together with enriched NO and Se concentrations characterize groundwater in the downstream the Porvenir zone. The geochemical age of this older, hill-slope groundwater suggests that its replenishment takes at least several decades when it becomes exhausted.
半干旱和干旱地区含水层的快速枯竭威胁着水资源安全。这在新兴国家尤其如此，由于对含水层系统缺乏了解，无法实施先进的管理措施，如含水层人工补给。本研究旨在为干旱和半干旱地区的含水层评估生成基准知识，在这些地区，再生水的人工补给正得到越来越多的重视。下加利福尼亚的瓜达卢佩含水层为墨西哥葡萄酒行业的 57%提供了用水。最近的计划设想通过从美墨边境转移处理过的废水来部分补充其枯竭的地下水资源，用于灌溉。在一场 236 毫米的强降雨期间，地下水位上升了约 20 米，这表明含水层具有快速响应能力，与自然补给相比，地下水位上升了约 20 米。基于地球化学多示踪剂方法，确定了两个主要的补给源：(a)现代水(<5 年，>1.8 TU)和近期-现代混合水(H 0.8-1.8 TU)，以及(b)1952 年前补给的次现代水(H < 0.5 TU)。第一种类型的水源于主要的瓜达卢佩溪流，其平均 δO 同位素值(-7.8‰)比当地平均雨水(-2.0‰)更贫化。溪流水最初具有 Na-HCO3 的组成，并补给整个卡利法西亚区和河谷内大部分河床下的地下水。第二种类型的水主要来自山坡地下水，其稳定同位素组成是当地混合雨水和 NaCl 的混合。高总溶解固体(>2 g l)以及丰富的 NO 和 Se 浓度是波文尼尔区下游地下水的特征。这种较老的山坡地下水的地球化学年龄表明，当其耗尽时，其补给至少需要几十年的时间。
