Rain water/ run off collection methods

[Otterbatcat]

I know there is much to research regarding this, I have seen a few systems with above and below ground cisterns and such. There is also slope on my land to retain run off.

Does anyone here have personal experience with diagnosing the capabilities of their property and functional methods of retaining water using these types of methods successfully, or have any recommended research?

 

[Maverick]

I use the roofs on all the buildings for collecting rain, the rain water goes into 800gal and 1500gal tanks, in many places in Utah many homes are built on top of concrete holding tanks using the roof and out buildings piping it in to the holding tanks.

The math
1000 square feet of roof yield 623 gallons of water per inch of rain.
Roof area (ft square) X rainfall ( ft ) X 7.48 gal/ft+ total rainwater ( gal )

example, if you want to calculate how much rainwater in gallons falls on your 55-by-80-foot ( 4400-square-foot) lot in a normal year where rain fall averages 12 inches. the calculation would look like this;
4,400-square-foot catchment area X 1 foot of average rainfall X 7.48 gallons per cubic foot = 32,912 gallons of rain falling on the site in an average year rain.

 

[Maverick]

Here's a simplified way for daily use
Web calculator you can use in inches of rain Vs foot though it don't take efficiency into account but close enough.

https://www.watercache.com/resources/rainwater-collection-calculator

 

[Otterbatcat]

Thank you for that link, I'll spend some time with it.

 

[Maverick]

Here are a couple of links that calculates you efficiency, little bit of a learning curve but very easy to use. Just find your property or house and draw out the parameter and it auto calculates your square foot and gather the information on your rainfall per month or take the year average and divide by twelve (not precise) and enter it in for each month.

http://save-the-rain.com/SR2/#

http://www.pequals.com/rain/

 

[user 5723]

I'm planning on using water catchment for my off grid future home. Need to leverage a ranch style floor plan to maximize building footprint (and keep low profile), which then allows me to have 5-10ft overhangs of the roof to expand roof catchment area. I'm sure we can conserve our water usage to extend our reserves, but I'm afraid that my family will want to maintain certain practices. We'll keep clothes washing to when needed, and we're looking to use a grey water system to flush toilets. I'm exploring ways to reclaim water from the septic from ceramic filters to dehumidifiers to even using a hoop house over plants in the leach field.

 

[tmttactical]

The design I plan on is also rain catchment. I figure a minimum usage (emergency drought year situation) of 20 gallons per person per day. Can you survive on less, absolutely but to maintain a reasonable life style and hygiene, then you will probably want to store 20 gallons per person / per day. Now you will have to figure in your annual rain fall and your roof / collection surface and then figure how much you are going to get per year to store. The more annual rain fall, the less surface and storage space needed. Your location and family size is going to determine the required surface needed, not the desired design. My selected area gets about 12 inches per year of rain fall, I will need to catch and store every drop I can. Another location gets about 60 inches per year, I could get by with a roof surface of a 1/4 of my current design. My suggestion, know where you are going to build before you work on any specific designs. Once you know the logistics, then you can design to meet your needs and desires. JM2C

 

[Mountain trapper]

Eventually I plan to catch the rain runoff from my barn, shop and house. Since these buildings are lower than my garden area about the only use this water would be is to keep a stock tank full and maybe a little early irrigation until summer, depending on the size of catchment tanks. We get about 12" - 16" of rainfall in spring and fall and near zero rain from June to September. In winter we get around 8' - 12' feet of snowfall. Since we have a very good deep well, with plans on drilling another well, I don't know just how benificial a water catchment system would be. But water is so precious here, especially in summer, that I hate to see any of it wasted.

 

[tmttactical]

@Arcticdude
Sun light, air and of course water. The key element of life. With your amount of rain fall and snow fall, I would consider maybe a deep, deep pond to collect rain and push snow into for the long summer months. Collect what you can, it can always be pumped or transported to where is can be useful. Even a slow moving wind turbine can keep a water tank full. There is always a use, getting it is the hard part, tough to make it rain on demand. At my chosen location, 12 inches of rain fall is it for the year. All irrigation will be down hill from the storage / collection tanks. Black water into septic system and recirculated to orchard. The gray water into mixed fertilizer irrigation system. All water will be re-cycled in one fashion or another. Every location has trade offs, plus and minus. We just have to pick what works best for each of us.

 

[AgapeReadiness]

Because the water table where I live is so low, especially in summer months, we collect 2000 gallons of rain water from our metal roofs.

We also have a wet weather creek that can be dammed up in no time at all.

Pond building is also something we've considered, but out in my area that's just asking for trouble with snakes.

 

[tmttactical]

To me, the difficulty is not collecting the rain, it is the storing what you have collected. in areas with a lot of monthly rain fall, it is not to big a problem. For us desert dwellers, the storage is the big issue.

 

[AgapeReadiness]

I definitely understand that! While we aren't necessarily in a desert, we tend to go roughly three months in the summer with very little to no rainfall. We do use the water for our animals and garden. We started with a 250 gallon tank, but that ran dry quick. We moved to a 500 gallon tank and that almost lasted the summer. Finally we added an additional 1500 gallon tank and so far so good, although it has been a crazy wet season!

 

[KateMTx]

I've thought about this idea as well - it seems so obvious and of course has a long history, yet so few people take advantage of it these days. Then there are the places where it's illegal (!) so you have to be careful. I'm glad it's working out for you. Ponds are nice because you can have a ready source of food (fish) if you keep them stocked, but they do take maintenance and of course snakes love them too.