The influence of flow‐through saline gravel pit lakes on the hydrologic budget and hydrochemistry of a Mediterranean drainage basin

Abstract

Flow-through brackish gravel pit lakes near the Adriatic Coast of Emilia Romagna (Italy) in the Mediterranean have a large influence on the hydrologic budget of the watershed. Strong evaporation in combination with intense drainage of the low lying basins enhances groundwater inflow into the lake. Precipitation falling on the lakes is mixed with brackish/saline lake water causing the loss of freshwater. The gravel pit lakes are characterized by a high salinity (TDS 5 4.6-12.3 g L 21 ) and high pH (8.5). Stable isotope data show that gravel pit lake water is fed by groundwater which is a mix of Apennine River water and (Holocene) Adriatic Seawater, subsequently enriched by evaporation. The slope of the local evaporation line is 5.4. Conservative tracer and water budget modeling shows that the final Cl concentration depends strongly on the ratio of evaporation to total inflow. Increasing drainage to compensate for sea level rise, subsidence or intense precipitation would enhance ground water flow into the lake and decrease Cl concentration while increasing evaporation would increase Cl concentration. Groundwater rich in dissolved trace elements flows into the gravel pit lakes that contains water with a higher pH and dissolved oxygen. Pit lake water remains enriched in some elements (e.g., Ba, Mo, Sb) and depleted in others (e.g., Fe, Ca, Zn, SO4) with respect to groundwater composition. The gravel pit lakes show limited eutrophication but the water quality should be monitored for trace elements (e.g., As) if they are to be used for recreational purposes.

Young gravel-pit lakes along Canada’s Dempster Highway: How do they compare with natural lakes?

“…The values obtained for our morphometric variables were consistent with other studies, as gravel-pit lakes were significantly deeper than natural lakes (Mollema et al 2015;Søndergaard et al 2018). Gravel-pit lakes also had a smaller surface area than natural lakes, consistent with the idea that these artificial lakes typically have a higher depth-to-surface area ratio (Blanchette and Lund 2016).…”

Sediment composition, provenance, and Holocene paleoenvironmental evolution of the Southern Po River coastal plain (Italy)

“…The Po River coastal plain is one of the largest alluvial plains in Europe. A large portion of the area suffers from issues related to sea‐level rise, such as strong coastal erosion (Taramelli, Di Matteo, Ciavola, Guadagnano, & Tolomei, ), marine flooding (Armaroli et al, ), and coastal aquifer salinization (Giambastiani, Colombani, Mastrocicco, & Fidelibus, ; Mollema, Antonellini, Dinelli, Greggio, & Stuyfzand, ; Mollema et al, ). Based on sea‐level rise predictions from recent glacio‐hydro‐isostatic models (Lambeck et al, ; Scarascia & Lionello, ), the Po River Delta and coastal plain will be increasingly vulnerable to future climate change scenarios (Perini, Calabrese, Salerno, Ciavola, & Armaroli, ; Sekovski et al, ).…”

“…Consequently, the comprehension of past coastal system dynamics (provenance, sediment transport, and sedimentation) in response to climate and relative sea‐level changes, and the evaluation of similarities between past and current environmental evolution are fundamental for future planning and management of the area. To properly manage groundwater resources in coastal areas, detailed geochemical characterization of the porous media at small and large scales is needed (Colombani, Mastrocicco, & Dinelli, ; Greggio et al, ; Mollema et al, ). In fact, the geochemical composition of aquifer deposits deeply affects groundwater quality (Griffioen, Klein, & Van Gaans, ; Hartog, Griffioen, & van Bergen, ; Von Brömssen et al, ).…”

The Effect of Artificial Recharge on Hydrochemistry: A Comparison of Two Fluvial Gravel Pit Lakes with Different Post-Excavation Uses in The Netherlands

“…The AR adds large amounts of PO 4 to DLV Lake but this does not lead to very high mean and increasing concentrations as it does for NO 3 (compare Figures 8 and 9). At least three processes play a role in P-cycling in lakes: (1) P is consumed by phytoplankton; (2) phosphor (P) may precipitate in lake sediments together with calcium (Ca 2+ ), metals (i.e., iron Fe 2+ ), and other (trace) elements such as nickel (Ni 2+ ) and arsenic (As 2+ ) [6,27]; (3) Internal loading of P by release from lake sediments [27][28][29][30][31][32]. Of these (1) and (2) are the most likely explanations for the disappearance of P from the water column in DLV Lake.…”