Investigating geochemical aspects of managed aquifer recharge by column experiments with alternating desalinated water and groundwater

Hydrol. Earth Syst. Sci.

et al. 2017

Self Cite

Abstract. We study the relation between surface infiltration and groundwater recharge during managed aquifer recharge (MAR) with desalinated seawater in an infiltration pond, at the Menashe site that overlies the northern part of the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple scales (up to the scale of the entire pond) by measuring the ponding depth, sediment water content and groundwater levels, using pressure sensors, single-ring infiltrometers, soil sensors, and observation wells. During a month (January 2015) of continuous intensive MAR (2.45 × 10 6 m 3 discharged to a 10.7 ha area), groundwater level has risen by 17 m attaining full connection with the pond, while average infiltration rates declined by almost 2 orders of magnitude (from ∼ 11 to ∼ 0.4 m d −1 ). This reduction can be explained solely by the lithology of the unsaturated zone that includes relatively low-permeability sediments. Clogging processes at the pond-surface -abundant in many MAR operations -are negated by the high-quality desalinated seawater (turbidity ∼ 0.2 NTU, total dissolved solids ∼ 120 mg L −1 ) or negligible compared to the low-permeability layers. Recharge during infiltration was estimated reasonably well by simple analytical models, whereas a numerical model was used for estimating groundwater recharge after the end of infiltration. It was found that a calibrated numerical model with a onedimensional representative sediment profile is able to capture MAR dynamics, including temporal reduction of infiltration rates, drainage and groundwater recharge. Measured infiltration rates of an independent MAR event (January 2016) fitted well to those calculated by the calibrated numerical model, showing the model validity. The successful quantification methodologies of the temporal groundwater recharge are useful for MAR practitioners and can serve as an input for groundwater flow models.

Section: Cloggingmentioning

confidence: 66%

“…This work is part of a comprehensive study involving field and laboratory investigations in order to better understand hydrological and geochemical processes during MAR with surplus of reverse-osmosis DSW in Israel (Ronen-Eliraz et al, 2017). The geochemical perspective of this field study will be reported in a future publication (Ganot et al, 2017).…”

mentioning

confidence: 99%

Monitoring and modeling infiltration–recharge dynamics of managed aquifer recharge with desalinated seawater

Hydrol. Earth Syst. Sci.

et al. 2017

Self Cite

“…The Menashe MAR site diverts the natural ephemeral flows from the Menashe Heights streams into a settling pond, and from there to three infiltration ponds. Production wells that encircle the site recover the recharged water from the aquifer (Sellinger and Aberbach, 1973). In the last few years, the southern infiltration pond is dedicated for the infiltration of a surplus of DSW from the Hadera SWRO desalination plant, located 4 km to the west, on the coastline (Fig.…”

Section: Study Areamentioning

confidence: 99%

Managed aquifer recharge with reverse-osmosis desalinated seawater: modeling the spreading in groundwater using stable water isotopes

Hydrol. Earth Syst. Sci.

et al. 2018

Self Cite

The spreading of reverse-osmosis desalinated seawater (DSW) in the Israeli coastal aquifer was studied using groundwater modeling and stable water isotopes as tracers. The DSW produced at the Hadera seawater reverse-osmosis (SWRO) desalination plant is recharged into the aquifer through an infiltration pond at the managed aquifer recharge (MAR) site of Menashe, Israel. The distinct difference in isotope composition between DSW (δ 18 O = 1.41 ‰; δ 2 H = 11.34 ‰) and the natural groundwater (δ 18 O = −4.48 ‰ to −5.43 ‰; δ 2 H = −18.41 ‰ to −22.68 ‰) makes the water isotopes preferable for use as a tracer compared to widely used chemical tracers, such as chloride. Moreover, this distinct difference can be used to simplify the system to a binary mixture of two end-members: desalinated seawater and groundwater. This approach is validated through a sensitivity analysis, and it is especially robust when spatial data of stable water isotopes in the aquifer are scarce. A calibrated groundwater flow and transport model was used to predict the DSW plume distribution in the aquifer after 50 years of MAR with DSW. The results suggest that after 50 years, 94 % of the recharged DSW was recovered by the production wells at the Menashe MAR site. The presented methodology is useful for predicting the distribution of reverse-osmosis desalinated seawater in various downstream groundwater systems.

“…The desalinated seawater is usually distributed directly to consumers through the national water grid. However, in operational situations in which large volumes (>10 5 m 3 ) of desalinated seawater cannot be distributed immediately, the expensive surplus DSW is stored through MAR operations (Ganot et al, ; Ronen‐Eliraz et al, ).…”

Section: Study Sitementioning

confidence: 99%

“…Here we study the geochemical processes during pond‐infiltration MAR with post‐treated, reverse‐osmosis DSW into a calcareous sandy aquifer with a 25 m‐thick unsaturated zone. The DSW composition (e.g., high Ca 2+ /Mg 2+ ; Ronen‐Eliraz et al, ) together with the relatively thick unsaturated zone creates unique conditions which distinguish this MAR site from other sites. Moreover, we use unsaturated zone and shallow groundwater field data to calibrate a mechanistic reactive transport model including cation exchange and calcite dissolution.…”

Section: Introductionmentioning

confidence: 99%

Geochemical Processes During Managed Aquifer Recharge With Desalinated Seawater

Water Resources Research

et al. 2018

We study geochemical processes along the variably‐saturated zone during managed aquifer recharge (MAR) with reverse‐osmosis desalinated seawater (DSW). The DSW, post‐treated at the desalination plant by calcite dissolution (remineralization) to meet the Israeli water quality standards, is recharged into the Israeli Coastal Aquifer through an infiltration pond. Water quality monitoring during two MAR events using suction cups and wells inside the pond indicates that cation exchange is the dominant subsurface reaction, driven by the high Ca2+ concentration in the post‐treated DSW. Stable isotope analysis shows that the shallow groundwater composition is similar to the recharged DSW, except for enrichment of Mg2+, Na+, Ca2+, and HCO3–. A calibrated variably‐saturated reactive transport model is used to predict the geochemical evolution during 50 years of MAR for two water quality scenarios: (i) post‐treated DSW (current practice) and (ii) soft DSW (lacking the remineralization post‐treatment process). The latter scenario was aimed to test soil‐aquifer‐treatment (SAT) as an alternative post‐treatment technique. Both scenarios provide an enrichment of ∼2.5 mg L−1 in Mg2+ due to cation exchange, compared to practically zero Mg2+ currently found in the Israeli DSW. Simulations of the alternative SAT scenario provide Ca2+ and HCO3– remineralization due to calcite dissolution at levels that meet the Israeli standard for DSW. The simulated calcite content reduction in the sediments below the infiltration pond after 50 years of MAR was low (<1%). Our findings suggest that remineralization using SAT for DSW is a potentially sustainable practice at MAR sites overlying calcareous sandy aquifers.