In planning stages, of hopefully a 2 acre cold-water pond in the foothills of the Rocky Mountains. As you can imagine, water is scarce. The most promising site has a 15 acre watershed, and would be fed by a combination of irrigation water (from a spring-fed stream) and a separate spring. My plan is to have aeration.

My question: is it a realistic option to construct such a pond without planned flow-through of water? Given the water situation, I would plan on a super compaction job of the pond basin. I know there would be some infiltration into the ground, but without any water flowing through I'm concerned about potential buildup of salts/perhaps heavy metals. There is no mining in the area. I am not concerned with managing nutrient loads. Thanks for any opinions!

Woody, lots of us in arid areas have limited overflow. I don't see a problem. However, you could install a syphon system if you want overflow.

Thanks! Good to know; seems like this would simplify things as you could then omit the outflow pipe? Obviously I would need an emergency spillway.

Welcome Woody!

With no regular flushing of your water, I'd bet nutrient loads will become an issue pretty quickly. Unless runoff brigs it in, or pumping is done near stream beds, there should be no issue with heavy metals at all. Most mineral salts provide some sort of benefit, but stagnated water that is never refreshed or filtered in a BOW will start to cause many issues in time.

Rainman - you mention that a factor relating to heavy metals would be if pumping is done near a streambed? Why is this? Do heavy metals accumulate in groundwater under streambeds?

Woody, unless a water is pretty acidic and dissolves a metal, it sinks to the bottom. Heavy Metals, when present are found in 2 type of fish...First in bottom feeding fish, and second, in fish that eat bottom feeding fish or other bottom feeding critters. Most heavy metals remain small, solid particles, Metals like Mercury, Rubidium and Bromine are some of the exceptions, remaining liquid. but un-dissolved in flowing water...these liquid heavy metals will widely disperse, but still do so on or near the bottom sediments

If the stream you pump water from has heavy metals and isn't pretty acidic (below a pH ~5.6), the metals are in the bottom sediments and only move or get redistributed when those sediments get disturbed, like in high water events, dredging, or sucking them into an intake hose.

Thanks, Rainman! Have high pH waters, but will definitely be doing some water testing. Nearby irrigation reservoir has a fish advisory for mercury for crappie, yellow perch, and BLUEGILL (who else has a bluegill advisory??) There is a statewide advisory for bass in Idaho, too. With all this around me, gotta be a concern.

Woody, we have those "advisories" around here also. What most of the alarmists never say, especially on Mercury, is that you'd have to eat over a ton of contaminated fish a year before any contaminant would become a concern in the human body...