Research On Non-natural Lakes Of Chilly And Arid Region Based On Isotope Technology And Hydrogeochemistry

Lake research of chilly and arid region are always highlighted by lake researchers due to high evapotranspiration and obvious seasonality. Wuliangsuhai Lake, which located at upper Yellow River Basin, Inner Mongolia, China, and Frank Lake, which located at Bow River Basin, Alberta, Canada, both selected for the research area because their same features as non-natural lakes. The conclusions are as follows:1. The meteoric water isotopes were analyzed in both research area and Local Meteoric Water Lines (LMWL) were published for the first time. All available historic data were collected for analysis.2. The stable isotopes data for all water samples were analyzed in both research area and δD and δ18O distribution features were discovered for the first time. Surface water and groundwater interaction was known preliminary that supported water and mess balances came out. Dual plot of δD and δ18O were given for two research area and stable isotopes evaporation equation as well. Besides evapotranspiration, the water-rock interaction also affects hydrogeochemistry based on deuterium-excess and TDS data. Groundwater research were discovered at both area based on isotopes technology, mini-piezometer installation and hydrogeochemistry analysis. The results indicated that the high concentration groundwater area at west of Wuliangsuhai Lake was discharged by the lake. For Frank Lake, no matter stable isotopes analysis or data of mini-piezometers, all proved that big account groundwater flow into the lake. This point was also known by the water and mess balance of Frank Lake.3. Based on stable isotopes technology, mineral saturation index, ion composition and ration, and hydrogeochemistry analysis, some conclusions were got as follows:The different water samples of Wuliangsuhai area have different hydrochemical types, especially the groundwater. But the lake water mix very well and almost have the same types.11of13wells exceed drinking-water guidelines for at least one health-based parameter and all wells exceed aesthetic guidelines. The well water is largely derived from Yellow River irrigation water. Notably high uranium concentrations in the Yellow River, relative to world rivers, suggest groundwater uranium and other trace elements may originate in the river-derived irrigation water. Complex hydrostratigraphy and spatial variation in groundwater recharge result in spatially complex groundwater flow and geochemistry. For Frank Lake, the hydrochemical types were not that same and affected by evaporation terribly. The major ions concentration increase with water flow direction except Calcium and TDP. Saturation index of Hydroxyapatite (Ca5(PO4)2) were calculated manually that indicated Hydroxyapatite were supper saturated at all water samples which was also proved by microprobe. Sulfate stable isotopes were also analyzed at Frank Lake research area, the result indicated the source of sulfate not just affected by human beings, but also affected by sulphide oxidation, soil solutions and atmospheric deposition. Usual mineral saturation index were almost all under saturated for both research area. Hydrogeology was affected by evapotranspiration, weathering, dissolution and precipitation, oxidation-reduction and mix in these two areas.4. The water and mess balances were established in these two areas based on collected data. The result indicated that Wuliangsuhai Lake discharge ground water. The salinity of Wulaingsuhai Lake was lost by discharge to Yellow River, reed harvest, discharge to groundwater and storage in the lake. Due to the special climate and geography of Frank Lake, a big account groundwater flow into the lake and most of the mess storage in the lake or part of them discharge to the groundwater.5. High pollution area of western Wuliangsuhai lake was invested and here are the reasons:1) This area was part of the lake in history, and then turned to ground due to lake area decrease. So the concentration of ions part of affected by lake sediment dissolution2) Groundwater was discharged by Lake water3) The groundwater flow to south was blocked by Wulaer Mountain4) Leakage of Tenth Canal5) Groundwater at the eastern of Wulaingsuhai Lake was hardly affected by lake water or irrigation water due to geological fault.6. Suggestions and ideas were given for non-natural lakes of chilly and arid area.