# Using bags of concrete to dam a small stream? **URL:** \ **Category:** Factual Questions\ **Created:** [December 15, 2018, 3:44am UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158 "2018-12-15T03:44:47Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [December 16, 2018, 3:08am UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/21 "2018-12-16T03:08:20Z")
Unfortunately, one more point to consider if fretting about the legal technicalities of creating a baby pool sized wading area for the ducks: If the stream is a “dry run” as we call it around here,(i.e., it is normally dry except during rain events), it falls under more lenient regulatory restrictions than a “wet stream” (carries water flow **all** the time). Just make sure those critters are licensed and registered with the proper authorities, their feed is non-GMO, and you clean your rain gutters twice a year.:rolleyes: ---
**Author:** ![RedSwinglineOne](https://avatars.discourse-cdn.com/v4/letter/r/a9adbd/32.png) [@RedSwinglineOne](https://boards.straightdope.com/u/RedSwinglineOne)\ **Post date:** [December 17, 2018, 9:36pm UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/22 "2018-12-17T21:36:54Z")
> [@Mangosteen](#): > > I’m just trying to make a 5 foot wide, 12 inch deep pond for my ducks, Jasper and Genevieve. Why don’t you just dig a hole? ---
**Author:** ![snowthx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowthx/32/10660_2.png) [@snowthx](https://boards.straightdope.com/u/snowthx)\ **Post date:** [December 18, 2018, 12:01am UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/23 "2018-12-18T00:01:17Z")
> [@RedSwinglineOne](#): > > Why don’t you just dig a hole? That, or just use local/natural materials, and make it look non-man-made. Hawaii has no shortage of rocks and sand - you could probably get what you need in the trunk of your car from the nearest construction site - probably the same amount of material as going to the hardware store. If anyone were to question you, you could just say it has always been there/the Hawaiians built it eons ago. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [December 18, 2018, 12:10am UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/24 "2018-12-18T00:10:39Z")
Dig a hole in the stream? It would quickly fill up with silt. Dig a hole in the ground? The soil here has a high percentage of volcanic cinder and drains quickly and they shit in the water constantly. The ducks love kiddie pools, but they shit so much in them that I can’t keep up with the cleaning. The stream pond idea eliminates the cleaning problem. ---
**Author:** ![GMANCANADA](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gmancanada/32/2837_2.png) [@GMANCANADA](https://boards.straightdope.com/u/GMANCANADA)\ **Post date:** [December 18, 2018, 1:02am UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/25 "2018-12-18T01:02:11Z")
Based on your comments, this may not work, but I was going to suggest digging a hole down but using a PVC pond liner over the volcanic cinder. It’s maybe not a cheap as the concrete option, but still only $34 for 7ftx10ft sheet, and possibly a lot easily to lug over than the cement. > **[TOTALPOND 7 ft. x 10 ft. Pond Liner Water Course 52250 - The Home Depot](https://www.homedepot.com/p/TOTALPOND-7-ft-x-10-ft-Pond-Liner-Water-Course-52250/202017064)** > > Make your small pond dreams a reality with the TotalPond 7 ft. x 10 ft. PVC Pond Liner. Suitable for use in water features up to 200 gallons, this multi-purpose liner is perfect for any project requiring ---
**Author:** ![Dinsdale](https://avatars.discourse-cdn.com/v4/letter/d/97f17d/32.png) [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Post date:** [December 18, 2018, 3:30pm UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/26 "2018-12-18T15:30:35Z")
The easiest course of action might be to get rid of the ducks! 😉 Good luck w/ whatever you choose to do. Just wanted to mention my experience when a family member was caught altering water flow on his property. Was a major hassle. But if you feel you’ll never get caught, and since there are no people downstream … ---
**Author:** ![pieceoftheuniverse](https://avatars.discourse-cdn.com/v4/letter/p/7993a0/32.png) [@pieceoftheuniverse](https://boards.straightdope.com/u/pieceoftheuniverse)\ **Post date:** [December 18, 2018, 5:08pm UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/27 "2018-12-18T17:08:51Z")
If you want your dam to last longer than a couple of years, you should definitely do more than just plop some bags of cement into the water. [Simple illustration of what happens to a river with a low head dam](https://www.youtube.com/watch?v=HOLFmDl4HM4&feature=youtu.be). Basically, it doesn’t take long for the sediment to pile up against the dam. Sediment management is a huge, huge problem with dams, even government-built ones with billions in funding. It takes careful management and construction to deal with sediment build-up. A [silt-trap](https://www.agric.wa.gov.au/water-management/de-silting-dry-dams#silttrap) is a good first step, though there is going to be a lot of sediment that’s traveling in the water that won’t reveal itself until it hits the dam wall. ---
**Author:** ![Arkcon](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Arkcon](https://boards.straightdope.com/u/Arkcon)\ **Post date:** [December 18, 2018, 5:50pm UTC](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158/28 "2018-12-18T17:50:00Z")
> [@Mangosteen](#): > > The ducks love kiddie pools, but they shit so much in them that I can’t keep up with the cleaning. Interestingly, waterfowl excrement can also help seal the bottom of your reservoir. Frank Herbert (of _Dune_ fame) did just that on his property, creating a pond that raised the local temperature a slight amount. Insert your own “_something something_ must flow” joke here. [Previous page](https://boards.straightdope.com/t/using-bags-of-concrete-to-dam-a-small-stream/826158.md?page=1)