Idea for an affordable rainwater collector

[vspin]

I'm not sure how well this idea would work, if at all, but I'd like to get input from you guys. I'm trying to create an extremely affordable rainwater collector for areas with little precipitation, and enough land. While this idea may be affordable, it does require a lot of labor.

My Rammed Earth Rainwater Collector Idea

The idea is to ram earth (not stabilized), creating a sloped rainwater collector surface with rammed walls around the perimeter to reject some dust and debris. After the collector is rammed, coat the surface with Henry's 887 Tropicool 100% Silicone Reflective Roof Coating. This coating is said to be 100 percent waterproof, "LIFETIME WARRANTY - One coat protects against extreme weather," and requires just one coat. I imagine you could maintain with more coats to specific areas needing to be touched-up.

Its location (away from floods) and ability to shed water away from the perimeter of the collector is important, I imagine, to avoid water eroding away the collector.

I have no idea if the coating would adhere to the rammed earth, or if this idea is just terrible. Any thoughts?

 

[Sanwizard]

Chemicals in the water a problem?

 

[vspin]

Chemicals in the water a problem?

According to Henry, this product is "tested and certified by NSF International in accordance with NSF Protocol P151: Health Effects from Rainwater Catchment System Components."

 

[Sanwizard]

Then go for it and let us know how it works out.

 

[toms]

Where i live it isn’t worth keeping water in open dams- evaporation is 1000mm/year (ie: more than rainfall)
We have a dam to catch flooding, it is lined with Bentonite which effectively seals it quite cheaply and is food grade.
I have built rammed earth walls before, for me they are a lot more expensive than buying a plastic rainwater tank.

Having said that, i would love to see you build your dam - i think it would be quite beautiful.

 

[vspin]

Thanks, but I'm not suggesting a dam, although after rereading what I wrote I can see why you think that, coupled with the possibility that I'm misusing terms. The rammed earth is only the sloped surface which diverts to a gutter, and then into a tank. The walls (short) are only there to keep some dirt and debris from getting on the sloped surface. For example, I'd like to create a 100' x 50' sloped surface to catch rainwater, and I've run the numbers on several rainwater setups (surface), and they're always expensive, and/or don't last very long.

Rainwater collection surfaces (100' x 50'):

-Corrugated panels - Really expensive but lasts up to 60 years. Panels alone are $7,320, and this does not include the fasteners, nor the cost of the huge platform it would be built on.

-Greenhouse plastic on rammed earth - Costs $500 every four years, and is not adhered to the rammed earth. Safe for drinking water?

-Misc. Materials - Often don't last long in sunlight, and may not be safe for drinking water.

-Silicone Roof Coating (Henry's) on rammed earth - Cost $3,490, mildew and algae resistant, safe for drinking water, and has a "Lifetime warranty" to handle extreme weather.

 

[Sparky]

Staying tuned...

 

[labeeman]

Thanks, but I'm not suggesting a dam, although after rereading what I wrote I can see why you think that, coupled with the possibility that I'm misusing terms. The rammed earth is only the sloped surface which diverts to a gutter, and then into a tank. The walls (short) are only there to keep some dirt and debris from getting on the sloped surface. For example, I'd like to create a 100' x 50' sloped surface to catch rainwater, and I've run the numbers on several rainwater setups (surface), and they're always expensive, and/or don't last very long.

Rainwater collection surfaces (100' x 50'):

-Corrugated panels - Really expensive but lasts up to 60 years. Panels alone are $7,320, and this does not include the fasteners, nor the cost of the huge platform it would be built on.

-Greenhouse plastic on rammed earth - Costs $500 every four years, and is not adhered to the rammed earth. Safe for drinking water?

-Misc. Materials - Often don't last long in sunlight, and may not be safe for drinking water.

-Silicone Roof Coating (Henry's) on rammed earth - Cost $3,490, mildew and algae resistant, safe for drinking water, and has a "Lifetime warranty" to handle extreme weather.

Builders plastic sheeting spread on the ground with a layer of gravel to protect it from the sun with the gravel the most expensive part.

 

[svetz]

Henry's 887 is what I have on my roof, a little pricey. The silicone has a dry non-slip grip that helps dirt/mildew adhere to any little indents. When wet it's quite slick. The "requires one coat" I'd be dubious about, when applying I don't know how you'd keep the dirt from inter-mixing, spraying perhaps?

What's the wildlife in the area like? I'd be concerned that they might puncture through the silicon membrane and tear it up over time.

I was thinking of collecting off the roof and making an enclosed 1000 gallon rectangular tank (4x4x8') from two by fours and MDF coated on the inside with fiberglass.

 

[RJuelfs]

I’d also worry about animal droppings. A roof system has a “first flush” feature. Tough to do on a system like that.

 

[vspin]

Thanks for the replies everyone. I'm going to address posts later but I wanted to post a response I got from Henry:

Unfortunately Henry 887 TropiCool would not adhere to rammed earth. For what you are doing I believe that you will need a rubberized sheet product. For Henry 887 to properly adhere the surface must be free of dirt and dust. Rammed earth is compacted dirt that is porous by nature and needs protection from long term exposure to moisture. There are water repellent additives that will waterproof the walls right through. However, you will have to check the toxicity.

 

[svetz]

I’d also worry about animal droppings. A roof system has a “first flush” feature. Tough to do on a system like that.

Thanks for posting the name of that feature! I knew I wanted such a device, but hadn't found them as I didn't know what they were called. As a newbie to the concept, there seems to be a lot more focus (or my search queries were mis-phrased) on automatic diverters.

...Henry 887 TropiCool would not adhere to rammed earth...

Oh well, possibly some water-safe plastic sheet covered with pea-rock so the UV won't break it down?

 

[12VoltInstalls]

I would landscape-rake your shed plane and merely cover the area with 6-mill plastic sheeting. Feed a settling tank (debris will precipitate out) that will avoid evaporating the water and then filter that into a separate tank for holding. Use the CDC dose of bleach to disinfect the water.

I personally have a 275 gallon square cube plastic tank I paid $60 for that I keep on a little trailer. Hauling water is therefore an option

 

[vspin]

My uneducated concerns with plastic sheeting then gravel:

-Cost of gravel plus delivery to cover 5000 sq. ft. of surface.

-Maintenance. I suspect that the plastic will eventually need replacing even if out of direct sunlight, which will require the removal of the gravel.

-Collector. I suspect that the gravel surface will not only catch rainwater, but also be very effective at retaining dust and debris as well, which would be difficult to clean.

-Would the gravel permit mold, mildew, bacteria, parasites, or the like to live beneath the gravel surface?

-Home for insects.


My uneducated concerns with just 6-mil plastic sheeting:

-Cost. ~$500 every four years. Actually, not too bad. I've seen plastic sheeting sold at a size of ~100' x 50' which would be great.

-Safe for catching rainwater to drink?


No matter the setup, walls may be necessary since the rainwater catch will be so close to the ground collecting dust and debris, and being exposed to animals. As I've said, these are my uneducated concerns based almost entirely on suspicion. I'd love to hear thought on my concerns.

 

[vspin]

I wonder if there's something affordable which can be applied over the top of the rammed earth that Henry 887 TropiCool would adhere to..?

 

[Bubba1]

Look up poor man's fiberglass. That might be an option.

 

[ghostwriter66]

find a local billbord company and purchase their used vinyl billboard advertisements after they use them .. i think we pay like $140 for the HUGE ones with no wind holes ...

 

[50ShadesOfDirt]

Living in my area, and finding out how hard the elements are on *anything* I build, I've determined that it's best to put up or build something "small", and let it go through a season (or two). If it survives that 1st cut, it could be worthy on larger scale projects. I have a diy modular fence panel system that I set up before the snows hit ... it survived that first test ... no large animal pushed it over, no weathering issues, etc.

So, do a small test case on each thing you propose or others have proposed, and see how each operates over a year (of seasons in your area); collect data at frequent points to extrapolate to larger sized projects; see how each holds up, and what unforseen things happened to them.

Some of my best-built projects, destined to win in every other category, lost out to a falling pine tree ... squashed like a bug.

 

[Smith]

 

[12VoltInstalls]

View attachment 53106

@Smith
Looks like you have a water heater like mine.

Where are you located?
Do I see snow?


I moved mine inside. That makes draining it every night for six weeks in the spring or four+ weeks in the fall unnecessary. If I heat the RV this year (likely; used to rent a ‘normal’ place Nov-April; this year I’ll be on my own property) the only thing I’ll need to do is move water storage inside and install a deep frost free hydrant. That’s really been a great water heater for me.