How To Build A Spring Water Catchment
Overview
Springs have been used by individuals and communities as water sources for ages. Their usually good water quality, and generally very low operation and maintenance requirements, make them choice water supplies for domestic purposes. Because these skills are so old, and demand for them is only recently making a resurgence, it's not easy finding proper information, but there are some great resources on this page.
The main objectives when making a spring water collection system are: 1. directing the spring's flow for practical uses without impeding it(which can hinder or entirely stop it's flow), and 2. protecting these water sources from contamination. Spring catchments make accessing spring water much easier than trying to scoop water out of the dirt.
There are a variety of different ways to construct a spring collection system. The method you use for making your spring water catchment might not be the method that's right for your neighbor. Each spring is unique and all designs need adapting to suit the type of spring and the topography. For example, some springs come out of a mountainside, and some seep out onto flat ground. Some springs have a flow rate of a gallon every 5 minutes, some, a gallon every 5 seconds.
The Basic Steps Are:
1. Locate the "eye" of the spring(the point at which the emerges from the ground) and removing surrounding debris
2. Prepare the eye of the spring
3. Build the headwall or spring box(depending on method chosen)
5. Run pipe to water reservoir or spigot
6. Maintain spring catchment area
Things To Consider Before You Begin
- Poorly constructed spring catchments, captures(or whatever you choose to call them), can lose their ability to effectively collect water almost immediately. Most poor construction is irreversible. For example, when water starts to seep from beneath a wall, it becomes extremely difficult to repair it.
- The lifetime of a spring catchment is limited by the durability of materials and affected by the exposure to weathering. With yearly cleaning and maintenance to repair any degradation to concrete work, spring catchments can typically function for up to twenty years.
- FYI - Spring flows can vary dramatically during wet and dry seasons, and discharge points of springs can shift over time, sometimes enough to impact the collection structure and its ability to properly collect all of the available water.
- If you have a choice between a high-production spring closer to your home site and a high-quality one farther up the hillside, choose the one farther up the hillside. Gravity is your friend.
Tips -
- If your spring has low pressure and you plan to run your pipe a good distance from the spring to your outlet, consider reducing the pipe size somewhere along the stretch of pipe to increase your water pressure at the spigot.
- Add a filter(such as a pool filter) within your plumbing to catch sediment or treat the water.
Time Of Year When Construction Should Occur
The construction of a spring box or spring water catchment should be done during the peak of dry season (late summer and fall) in order to identify and use only the most reliable springs.
Testing A Spring's Flow Rate
When you consider using a spring as your main water source, a few things should be taken into account. If possible, the flow rate for your spring should be monitored for an entire year, but it is most critical to measure the flow rate during late summer and fall when groundwater levels and spring flows are usually at their lowest.
A good rule of thumb is that springs used for drinking water supplies should yield at least 2 gallons per minute throughout the entire year unless water storage is going to be used. The amount of water you will need from your spring depends entirely on your household’s daily water needs. Water needs for an individual home vary depending on water use, water storage, and water-saving devices within your home. For reference, the average modern American home requires approximately 50 to 75 gallons of water a day per person. If you're trying to live in a more "resource conservative" manner, or get water from a variety of sources, you might require less.
The flow rate of a spring can be tested by digging a 5-gallon bucket into the slope of the spring and allowing the water to flow into the bucket. Determine the flow rate by timing how long it takes the water to fill the bucket.
Quantities of water flowing over a poorly defined channel of mud and rocks may be difficult to measure. The best approach is to channel the water into one path and measure a single stream.
Supplies For Building A Spring Catchment
These are very general and quantities and materials will vary according to your plan. Read on to learn more.
1. PVC Pipe
2. Small boulders
3. Gravel (1/2" to 2")
4. Cement or puddled clay
5. Waterproofing
6. Cement Forms - cut boards, nails
What Characteristics Should A Developed Spring Have?
- A surface water diversion ditch uphill from it in good repair - A surface water diversion ditch should be dug above and around the area of the spring because water running across the surface, especially in the rainy season, can contaminate the spring.
- Latrines should be at least 100 feet downhill from a spring
- Keep animals away from the spring area - farm animals should never be uphill from a spring catchment, and should be kept a minimum of 100 feet away(the farther, the better) to prevent contamination.
- A protective fence or hedge should be built around the spring area
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Types Of Springs
Non-seepage springs, also described as "concentrated" springs, and low area springs are the most common springs used as drinking water.
- Non-seepage or Concentrated springs are usually located at the base of mountains or hillsides and can be easily developed. Surface water drains away from this type of spring which makes it easier to protect from contaminants.
- Low-area springs are found in valleys and low-lying areas. The development of low-area springs requires more care because of the increased potential for contamination from surface water.
- Seepage springs are the most difficult to develop. They are easily contaminated because groundwater is collected over a wide area from sources that may be very close to the surface. During periods of drought, seepage springs may dry up completely.
Is A Spring Box Necessary?
Many publications describe the protection of springs from contamination using spring boxes. However, in many cases a spring box may not really be necessary. Protecting a spring without using a spring box assumes a gravity spring with a flow rate of up to about 10 gallons(or 35 liters)/minute.
Use of the design with higher flow rates is possible in some instances, but more than one delivery pipe and a larger concreted hollow or "sump" behind the headwall are recommended for such flows.
In a technical brief from the collection Running Water(Shaw, 1999), spring boxes are described, and an alternative design is presented.
An alternative to building a spring box can be used if water can be protected and collected without a spring box, if no sedimentation is needed, and if no storage box is required. The technical brief describes the essential parts to protecting a spring without a spring box, including site selection, excavation, construction of the headwall, and is a valuable resource addressing all types of off grid, water related projects.
The approach is a way to protect the spring as it naturally flows, accounting for shifts in geology through time and capturing the full amount of water, while using the most practical amount of materials. There is no specialized skill involved with the construction of these spring captures.
Advantages Of Protecting A Spring Without The Use Of A Spring Box:
1. Simpler design
2. Quicker construction
3. Suits flatter sites
4. Reduced cost
5. No provision is needed for the depth of the storage/sedimentation chamber
A Spring Box Can Be Useful As:
1. A sedimentation chamber where particles of sand carried in the spring water can settle out. However, spring flows tend to carry little sediment material, and generally do not require a large collection tank for sedimentation purposes. Any sediment that may be present is primarily settled out or filtered in the spring.
2. A storage chamber which is useful for springs where the demand for water exceeds the flow rate of the spring.
3. A method of protecting the spring water from contamination.
4. A way of collecting the spring water by giving it an easy
flow path from the aquifer into a delivery pipe.
Determine Whether Or Not To Use A Spring Box
You might want to consider foregoing a spring box altogether if...
1. Water from a spring can be protected and collected without a spring box,
2. and if no sedimentation is needed because the water carries only a low level of suspended solids,
3. and if no storage is needed because the spring flows at a rate sufficient to meet the peak demand...
then no spring box is required.
What Characteristics Should A Spring Box Have
For maximum protection against contamination, a properly developed spring should have the following characteristics:
- The size of a spring box depends on the amount of storage required. Ideally the box should be at least 4 feet deep and should extend at least 1 foot above the ground. The median size of a spring box is 4' x 3' x 3' and 60 square feet of improved, protected area. This size will accommodate most springs.
- absence of contamination sources
- a collection system to concentrate and channel the flow (e.g., a cutoff wall or a system of perforated pipe located where the water is at least 3 feet below the surface)
- additional storage tank and disinfection equipment, if necessary
- A properly constructed spring box will have a watertight cover that fits like a shoe box lid. This will prevent insects, animals, and surface water from entering the spring.
- A spring box should not contain silt or animals(I should hope not! lol)
- the space behind the box should be sealed with puddled clay or concrete plinth(slab).
- You will typically want to have 4 pipes on your spring box. These are:
1. The inlet pipe - where the water enters the spring box
2. The exit pipe - where your water leaves the spring box and goes to: either another containment tank(usually necessary if you have a low flow rate and need access to a larger volume of water than the spring catchment provides at any given time), or, straight to your spigot.
3. A washout pipe - This is simply a pipe installed in or near the base of the box that can easily be opened so that sediment and trash can be flushed out.
4. An overflow or vent pipe. This pipe is installed on or near the top of the spring box, and run away from the area. If your flow rate exceeds the spring box's capacity, the excess water needs somewhere to go. Remember that if you block a springs flow, it can completely divert it's emergence from the ground to somewhere inaccessible. The end of your vent pipe should be covered by a screen to prevent critters and other things from getting into the spring box from the outside.
A cement spring box under construction
Featured Video -
Taibuk Village Clean Drinking Water Project
How To Build A Spring Box
Before you dive in here I encourage you to read over the information on the "How To Locate Water" page if you're not familiar with "water bearing layers" and "impermeable layers".
Traditionally, spring boxes were made of cement, but a variety of containers can be used; stone masonry, ferrocement, fiberglass, or plastic reservoirs(See videos on this page). Below is a broad overview of spring boxes and their construction:
There are 2 main types of spring catchments.
1."Against the earth" - constructing a spring box against the earth using cement
2. A "piped spring" - a pipe is run from the spring eye to a "spring box"
These two types can be seen in the images above.
Step 1. Clear away any debris that's blocking the origination of the spring(the "eye" of the spring). Follow the flow of the spring, just above the impermeable layer of earth. It's preferable to use hand tools, since you'll want to follow the course of the spring gently. Clear back into the
earth as far as you can go without digging into the impervious layer and without impeding the spring's flow. When you have both a clear sight of the spring's eye, and the layer of earth above the eye is roughly 4 to 6 feet thick, you are ready to move on to the next step. The layer of earth helps to protect the spring.
*No attempt should be made to change the spring‘s natural course. If there is any obstruction, the spring can disappear and discharge somewhere else.
Step 2. Divert the spring to the side temporarily so you have a fairly clean place in front of the spring eye to install your spring box. If you've ever watched a show about dam building you know that they divert rivers temporarily so they can construct the dam. It's the same idea here but on a smaller scale. This is normally achieved with a dam made of clay and the use of a temporary pipe.
Step 3. This step is determined by which type of spring box you've decided to build. When you get to this phase of construction, keep in mind that gravity is your friend. You want your inlet and exit pipes, and your spring box, all at a gradual downhill slope from the spring eye.
Now you will: lay down the pipe that will run from the spring eye to the spring box, and/or, get ready to begin construction of the base and rear spring box wall, and/or, prepare the spot for your container if using something other than cement. In any case, you'll be adding 1/2 " to 2" sized gravel in front of the spring's eye. This supports the water bearing layer so it doesn't wash out while allowing the spring to flow.
For more in depth information, please refer to these PDF's(I have set them to open in separate pages so you can view them simultaneously if you'd like) -
Harnessing A Spring Without The Use Of A Spring Box
Instead of recreating what's already well constructed, step by step info, check out the pdf - Protecting Springs - An alternative to spring boxes provided by Loughborough University. This type of catchment is best for springs with up to a 10 gallon/minute flow rate.
Operation and Maintenance
Spring catchment flushing is recommended once a year to remove sediment and screens cleaned to remove buildup.
Grass is the only thing that should be allowed to grow above and around the spring catchment area so tree and shrub roots don't block pipes or crack the cement. Grass is also necessary to allow surface water to penetrate the ground and recharge aquifers, and helps minimize the erosion of your spring catchment area.
Maintenance is carried out by controlling human and animal activities around the spring, repairing the perimeter fence if one is used, and repairing the surface water drainage system. It is also necessary to monitor the growth of trees around the spring to prevent roots from causing problems. Periodic testing of the water for bacterial contamination is also recommended.
Credit For Content:
United Nations Environment Programme-Division of Technology, Industry and Economics
USAID.gov
Unicef
WHO - World Health Organization
Penn State Extension - Department of Agricultural Services
WEDC Loughborough University Leicestershire, UK
Michigan Technological University - Improvements in sustainability of gravity-fed water systems in the COMARCA NGÄBE-BUGLÉ, PANAMA: spring captures and circuit rider model
Michigan Technological University
Peace Corps
This is an image of a community spring's diversion ditch. Yours probably won't be this large, but you get the idea.
Below Are Some Spring Box Design Examples:
This design runs a pipe between the spring's "eye" and the spring box.
A spring box built against the earth.
A spring box built using stone masonry.
A spring box with a headwall, wing walls, and a concrete plinth to prevent surface water from entering.
A variety of containers can be used as a spring box, like a round cement reservoir. Add your own pipes.
A Washout Can Easily Be Built Right Into The Base Of A Spring Box For Easy Cleaning.
Featured Video -
Spring Catchment - Using PVC Tubes
