Couple of things I notice looking at that lake.
- first, the time lapse doesn't clearly show the lake growing in size. to me it seems to show the lake swells and shrinks depending on the inflow and the evaporation/seepage.
- second, it looks to be in the flood plain of the pecos river, which would have an affect.
- third it looks like one of those west texas irrigation ditches flows into the "lake"
these things are relevant because that lake has been there for a while, and that portion of the pecos river has a TDS of around 16,000 mg/l with chlorides in the 5k-6k mg/l range. for reference that is higher than the definition for brackish. but not quite seawater which is ~35k mg/l tds and 19k mg/l chlorides. freshwater for reference should have TDS below 500 and chlorides below 250. so you could very easily get to the levels seen in that lake with nothing but the pecos river as a source and evaporation/seepage as the outflow.
now, those wells are a problem and are likely contributing to the issues seen in that lake, but my guess is that plugging the wells doesn't completely solve the problem.