RAINWATER HARVESTING

[Jonesie]

RAINWATER HARVESTING

A rainwater collection and storage system is investigated, focusing on water quality at various points: from roof runoff to an underground concrete cistern. A prototype sand filtration system (designed to improve water quality) is built and then tested.
The result is complete removal of suspended solids.

http://www.uoregon.edu/~hof/S01havestingrain/

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Introduction

Anita Van Asperdt and Eimar Boesjes treat rainwater as a valuable resource rather than a problem. The metal roofs of their newly constructed house are designed to collect and direct rainwater into an 8,000-gallon underground cistern where it is stored for later use. According to rooftop collection potentials, the typically wet winters of Oregon will provide them with enough water to irrigate their landscape and perhaps reduce their dependence upon municipal water utilities for indoor use.

Located in the south hills of Eugene, Oregon, the house is perched on a steep slope surrounded by Douglas fir woodlands. Rainwater from two of the four roof planes is harvested and stored in a concrete cistern while collection from the other roofs is diverted through a backyard streambed and ultimately into the abutting wetlands.


Fig. 1: Rainwater collection system
Fig. 2: Filter placement detail


The rainwater catchment system consists of painted steel roof structures (potable-safe coating). The water is artfully channeled from the rooftop to truncated downspouts that spill onto granite boulders at ground level. (see fig. 1) These boulders sit atop concrete footings that house pipes leading to the cistern inlets.

At present, the system is devoid of any filtration system to help purify stored water. The owners intend to add sand filters (fig. 2) and perhaps eventually supplement their system with additional means of filtration and/or sterilization in order to raise the water quality to potable standards.

After our initial tour of the home, we generated numerous questions for investigation. The discussions that ensued eventually led to the formulation of a hypothesis.

http://www.uoregon.edu/~hof/S01havestingrain/intro.html

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Data & Analysis

Part 1 - Baseline Analysis of Rainwater Samples

Six common water quality tests were performed on five water samples to provide background on water quality issues relevant for rainwater harvesting. This process aided in formulation of a study experiment and provided context for the results.

pH
pH levels in the cistern water were predictably high due to leaching within the concrete structure. This is a standard chemical reaction with new concrete and will require a full flush to remedy the problem. Both the metal and shingle roof samples however were low, or acidic, in comparison to the EWEB norms. This is expected for rainwater.

Turbidity
The asphalt shingled roof was the most turbid, as was expected given its brownish color. This roof structure was not designed nor is it maintained for rainwater collection and was sampled to display the difference in water quality. Tap water collected at Moonshadow Drive tested higher than EWEB standards with regard to turbidity. This is reasonable since the water is bound to pick up some sediment during distribution.

Conductivity
Rainwater in its natural state, is very close to de-ionized but after passing over the zinc based anti-moss compound found on the shingled roof structure, conductivity is much higher.

Hardness
In its natural state rainwater is very soft and this tested true of the samples collected from the metal roof. There is little opportunity for the water to absorb minerals running off a smooth metal surface. After passing over the granite boulder and then into the cistern the water hardness levels begin to rise.

Total Suspended Solids
Given a chance to settle out, one would expect sub-surface cistern water to have fewer suspended solids than water sampled from the inlet. In this case however, bits of flocculant scum floating in the cistern water suggest bacterial activity, the presence of organic food matter, and thus suspended solids.

Coliform Colony Counts
Coliform counts presented here are not scientifically accurate since the collection containers were not sanitized prior to sampling. It is interesting to note however that residual chlorine in the tap water prevented any coliform growth in that sample.

http://www.uoregon.edu/~hof/S01havestingrain/data.html

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Data & Analysis

Part 2 - Prototype filter sample analysis

These samples are not directly comparable to the ones tested in our baseline investigations. This is because we combined all rainwater samples and added organic matter (dirt, leaves, and twigs) to simulate a "first flush". However, it is interesting to note that our filter effluent was in the same range as EWEB's finished water, indicating the prototype was very effective in removing suspended solids.

In addition to (or perhaps as a result of) suspended particle removal, our prototype filter also removed all traces of color in the sample pictured above.

http://www.uoregon.edu/~hof/S01havestingrain/data2.html

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Conclusion

Based upon our prototype testing results, we conclude that a sand filtration system will effectively eliminate all suspended solids and therefore improve the quality of stored rainwater at the Van Asperdt-Boesjes residence.

Because organic particles are removed from rainwater by the sand filter before entering the cistern, the potential for bacterial growth is drastically diminished. Such a filtration system could be easily implemented into the current design and will result in significant water quality improvements.

It should be mentioned however, that the elimination of suspended solids does not equate to water potability. To meet EPA standards for safe drinking, water samples should be tested by a certified laboratory. Many owners of rainwater harvesting systems use chlorine, ozone, or UV purification to ensure that their drinking water is free of pathogens.

This case study allowed us to learn about water supply on two very different scales. At the community scale, EWEB's Hayden Bridge facility embraces water in a technical manner with a huge supply flume that runs directly through the building's second floor landing. On a residential scale, the house at Moonshadow Drive celebrates water in an artistic manner with streams of rainwater falling over granite boulders. There is also an HVAC intake in the cistern that provides cooler air to the house, and an acoustic connection (through vents) to the water dripping into the cistern. By using water as an organizing principle, the owners of these two buildings of very different scale have found a way to address their environmental control needs and make the architecture special at the same time.

Rainwater Harvesting is a Vital Signs Case Study
prepared by Angela Matt and Joshua Cohen, Spring 2001.

http://www.uoregon.edu/~hof/S01havestingrain/conclusion.html

[LMonty]

Re: RAINWATER HARVESTING

nice find, johnsie. thanks!

[Blue]

Re: RAINWATER HARVESTING

Wow, this is good. I wish that we could do this.

[Jonesie]

RAINWATER HARVESTING -TAMU

http://rainwaterharvesting.tamu.edu/

RAINWATER HARVESTING
How to develop a rainwater harvesting system for your landscape

Efficient water use is increasingly important to
the Western United States. With the growing
population and limited supply of both
groundwater and surface water, homeowners
must use water wisely. Rainwater harvesting
is an innovative approach anyone can use.

Harvesting rainwater for use in the home landscape:

? Saves you money by reducing your water bills.
? Reduces demand on the municipal water supply.
? Makes efficient use of a valuable resource.
? Reduces flooding, erosion and contamination
of surface water with sediments, fertilizers and
pesticides in rainfall run-off.

Why Harvest

Can rain save you money? Yes. Even if you live where annual rainfall averages only 12 inches, you can save money by collecting and storing rainwater and using it to irrigate your trees, shrubs and lawn.

Efficient water use is increasingly important to the Western United States. With the growing population and limited supply of both groundwater and surface water, homeowners must use water wisely. Rainwater harvesting is an innovative approach anyone can use.

Rainwater harvesting captures, diverts and stores rainwater for later use. Rainwater can even be used for drinking, with proper treatment. But the easiest way to use stored rainwater is for landscaping. In many communities, 30 to 50 percent of the total water is used for landscape irrigation. If that demand for a limited natural resource can be reduced, everyone benefits.

Harvesting rainwater for use in the home landscape:

? Saves you money by reducing your water bills.
? Reduces demand on the municipal water supply.
? Makes efficient use of a valuable resource.
? Reduces flooding, erosion and the contamination of surface water with sediments, fertilizers and pesticides in rainfall run-off.

Rainwater is good for plants because it is free of salts and other minerals that harm root growth. As rainwater percolates into the soil, it forces salts down and away from root zones, allowing roots to grow better and making plants more drought tolerant.

Rainwater harvesting can be used both in large-scale landscapes, such as parks, schools, commercial sites, parking lots and apartment complexes, and in small residential landscapes.

Whether your landscape is large or small, developed or new, the principles described on this Web site can help you install a rainwater harvesting system.
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How It Works

A rainwater harvesting system consists of the supply (rainfall), the demand (water needed by plants), and a system for collecting water and moving it to the plants. Simple systems distribute rainwater immediately. Complex systems store some or all of the rainwater for later use.

Rainfall.
?Run-off? is the rainwater that flows off a surface. If the surface is impermeable (for example, pavement, concrete, roofs), run-off occurs immediately. If the surface is permeable, run-off will not occur until the surface is saturated. Run-off can be harvested (captured) and used immediately to water plants or stored for later use.

Plant Water Requirements.
The types and numbers of plants in your landscape, along with their growth stages and sizes, determine the amount of water your plants need to be healthy. Because rainfall varies throughout Texas, different plants have become adapted to conditions in different regions of the state. Plants native to your region are the best choices for your landscape because their water requirements are usually met by normal rainfall amounts.

Water Collection and Distribution System.
Rainwater collection and distribution systems can be incorporated into almost any existing site, although it is easier to incorporate them into new construction.
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Simple Systems


About Simple Systems

A simple water harvesting system usually consists of a catchment, a distribution system and a landscape holding area, which can be a concave or planted area with a border or earthen berm to retain water for immediate use. Gravity moves the water from the catchment (for example, the roof) to a different location. Sometimes water is caught in small containers and stored for later use. Water dripping from the edge of a roof to a planted area or a diversion channel located directly below the drip edge is an example of a simple water harvesting system.

Catchments.
A catchment is any area from which water can be collected, including roofs, paved areas and the soil surface. The best catchments have hard, smooth surfaces, such as concrete or metal roofing material. The amount of water harvested from a catchment depends on its size, surface texture, slope and rainfall received.

Distribution Systems.
Distribution systems channel water from catchments to landscape holding areas. Examples of distribution systems include gutters and downspouts, sloped sidewalks, hillsides, street and parking lot curb cutouts and channels, ditches and swales. If gravity does not cause water to flow though your distribution system, you may need to install a small pump, gates or diverters. You may need to line earthen distribution systems with an impermeable material such as plastic to keep water from soaking into non-target areas. Complex distribution systems, discussed later, also may include pipelines.

Landscape Holding Areas.
Concave depressions covered by grass or plants can store water for direct landscape use and reduction of flooding and erosion. Several such holding areas can be chained together through spillways. You can create holding areas by digging out depressions and keeping the resulting soil as a berm or by using berms, moats or soil terracing to make flat areas hold water. You should, however, be aware that digging may expose poorer quality subsoils unsuitable for landscape plants.

Designing and Building a Simple Rainwater Harvesting System

Step #1. Design the Collection and Distribution Systems.

Observe your landscape during a rain to identify its drainage pattern, and then use that pattern to decide how to move water from catchments to plants. Ideas for collection/ distribution systems include:

? Use your roof to collect rainwater, then extend downspouts, provide paths or use hoses to move the water to plants.
? Use existing sloped paving to reach plants.
? Design new sidewalks, terraces or driveways with a two percent ( 1/4 inch per foot) slope toward plants.
? Grade unpaved, bare soil to increase and direct run-off.
? Design landscape soil and plantings around foundations to slope away from buildings.

Step #2. Design Landscape Holding Areas.

Next, identify landscape depressions with potential for holding water or create new ones near plants. Tips for designing landscape holding areas include:

? Locate holding areas at least 10 feet away from buildings to avoid structural or pest problems.
? Build level berms or moats around plants to avoid damaging roots, but do not mound soil at plant bases.
? To encourage large root systems, extendholding areas beyond the ?drip line,? the outer perimeter of possible run-off from the catchment. (Plants with well-developed root systems are more drought tolerant.)
? Locate new plants at upper edges of concave holding areas to encourage large root systems and to protect them from flooding.
? Connect several holding areas with spillways or channels to distribute water throughout your site.


Step #3. Select Plants.

To help your water harvesting project succeed, choose native or regionally adapted plants that can withstand both prolonged drought and prolonged inundation. For example, excess water may collect at the bottom of a holding area due to soil saturation, so low-water-use, native riparian trees may be the best choice for large, deep basins.

To determine the best plants for your region, consult a guide such as Xeriscape?Landscape Water Conservation, publication B-1584 from Texas Cooperative Extension, a part of the Texas A&M University System. Other plant lists and resources are available at the Texas Master Gardeners? Web site: http://aggie-horticulture.tamu.edu/mastergd.mg.html or http://aggie.horticulture.tamu.edu/e...lications.html.

To seed holding basins, select seed mixes containing native or adapted wildflowers, grasses and herbaceous plants. Perennial grasses will hold the soil and prevent erosion.

Compacting soil in landscape holding areas inhibits the movement of water through the soil. Loosen compacted soil by tilling. Add organic matter such as compost to soil that is too sandy to hold water. To reduce evaporation, apply a 1.5-to-2-inch layer of mulch after planting. Organic mulches may increase permeability of tight clay soils but may float if inundated.

Tips on how best to use water free-falling from roof downspouts include:

? Plant large, rigid plants where the water falls.
? Hang a large chain from the downspout to the ground to disperse and slow the water.
? Provide a storage basin to slow the falling water.
? Place rocks or other hard materials under the downspout to prevent erosion by breaking the fall of the water.
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Complex Systems


About Complex Systems

To maximize the benefits of rainwater harvesting, complex systems build in storage to provide water between rainfall events. But can such systems collect and store enough rainwater in an average year to irrigate an entire landscape? Yes, if the amount of water harvested (the supply) equals the amount of water needed for irrigation (the demand). Complex water harvesting systems use stored water to balance the supply-demand equation during limited rainfall periods.

Complex rainwater harvesting systems cost more to build but yield greater water savings than systems without storage. Consider the following factors when deciding whether to invest in a complex water harvesting system:

? Availability of other water supplies for irrigation.
? Need for professional assistance to design and construct a complex system.
? Cost of storage, including the storage container, excavation, pumps, wiring and on-going maintenance.
? Long investment payback period (sometimes several years).
? Personal commitment to ?water conservation ethic.?

To reduce the cost of a complex system, you can (1) build a smaller storage container, harvesting less than the total irrigation water your landscape needs; (2) limit landscape area or reduce plant densities, lessening water demand; or (3) replace high-water-use plants with medium- or low-water-use ones, also reducing the amount of irrigation water needed.

How a Complex Rainwater Harvesting System Works

Complex rainwater harvesting systems include catchments, conveyance systems (connecting catchments to storage containers), storage, and distribution systems (directing water where it is needed).

Catchments.
The amount of water or ?yield? that a catchment provides depends on its size and surface texture. Examples of various surface textures include:

? High yield: Concrete, asphalt or brick paving and smooth-surfaced roofing materials such as metal.
? Medium yield: Bare soil (compacted clay soils yield the most).
? Low yield: Areas with plants, such as grass or groundcover (plants hold water longer, allowing it to infiltrate into the soil rather than run off).

Conveyance Systems.
Conveyance systems direct water from catchments to storage containers. Roof catchment systems use canals, from which water flows by gravity into storage containers, or gutters and downspouts, which should be sized to collect as much rainfall as possible. (See Appendix VI for guidelines on gutters and downspouts.)

Storage.
Storage makes rainwater available when needed.

Filtration.
Before water is stored, it should be filtered to remove particles and debris. Filtration considerations include:

? Degree of filtration:
Depends on the size of the distribution tubing and on the emission devices used. For example, microirrigation drip systems require more and finer filtering, with an additional filter at the system inlet, than do hose distribution systems.
? Type of filter:
(1) In-line;
(2) Leaf screens, placed over gutters at the top of the downspout;
(3) Diversion by roofwashing with a 4-to-6-inch PVC standpipe (with a valve and bottom cleanout) connected to a gutter downspout. The first rainfall that falls, at a rate of 10 gallons for every 1,000 sq. ft., fills the standpipe, and the rest flows to the downspout connected to the cistern. When the rain stops, the standpipe is drained in preparation for the next rain.

Containers.
Storage containers may be made of polyethylene, fiberglass, wood, concrete or metal. Underground containers cost more to excavate, to maintain or to remove, and the need to pump water out of them adds to their cost. Swimming pools, stock tanks, septic tanks, ferro-cement culverts or containers built from concrete blocks, poured-in-place concrete or building rocks can be used for underground storage.

Costs for above-ground storage containers depend on the type of catchment and conveyance system, the degree of filtration and the distance between the container and the area irrigated. Examples of containers that can be used for above-ground storage include 55-gallon plastic or steel drums, barrels, tanks, cisterns, stock tanks, fiberglass fish ponds and swimming pools, as well as buildings or tanks made from concrete blocks, stone, plastic bags filled with sand, or rammed earth. Look under ?Tanks,? ?Feed Dealers,? ?Septic Tanks? or ?Swimming Pools? in a telephone directory to find sources of storage containers. You may be able to salvage 55-gallon drums from local businesses, but use only drums free of toxic residues.

Tips for storage container placement and use include:

? Elevate above-ground storage containers to take advantage of gravity flow; for example, place them at the high end of a sloped lot.
? Put storage containers near plants and near or at the end of downspouts.
? Build concave planted areas to allow rainwater to percolate slowly into the soil.
? Hide unsightly containers in an unobtrusive place or behind a structure, screen and/or plants.
? Because smaller cisterns are easy to handle and camouflage, place several of them near the irrigated site.
? For large landscaped areas, connect several tanks to increase storage capacity.
? If rainfall exceeds storage capacity, provide alternative storage for the excess or allow it to spill out. Make sure storage container inlets and overflow outlets are the same size.

Distribution.
The distribution system channels water to plants from storage containers, using garden hoses, constructed channels, solid or perforated pipes or manual drip systems, plus (for some systems) gates and diverters to control flow rate and direction. If your system is gravity-fed, you may need to put a manual or an electric valve near the bottom of your storage container. If your system is not gravity-fed, connect an electric pump to a garden hose to transport water to the irrigation site. Drip and other types of integrated distribution systems need pumps to provide necessary pressure for system operation.

If there is not enough rainfall to meet your irrigation demands, add water to your container from an auxiliary source to avoid building an alternative system. If you connect your system to a municipal or private water supply, you must use an ?air gap? or other approved backflow prevention device. If you decide not to use a supplemental water source, make sure any pumps turn off automatically when your tank is empty. (Integrated distribution systems are complex; make sure to comply with local plumbing and building codes.)

Designing and Building Complex Rainwater Harvesting Systems

Steps involved in designing a complex water harvesting system include site analysis, calculations, system design, construction and field testing. For large projects or those with several catchments and planting areas, divide the project site into sub-drainage areas and repeat these steps for each.

Step #1. Site Analysis

Follow these steps in analyzing your site:

? Draw the site to scale, using arrows to plot existing drainage patterns observed during a rain and showing high and low areas on your sketch.
? Identify possible catchments, such as pavements, roof surfaces and bare earth.
? Identify areas requiring irrigation and sites near them where storage could be located (either above ground or underground).
? Think about ways to move water from catchments to holding areas or storage containers. (Use gravity wherever possible.)
? Think about ways to move water through the site from one landscaped area to another.

Step #2. Calculations

To design a complex water harvesting system, you must first calculate monthly ?Supply? (rainfall harvest potential) and monthly ?Demand? (plant water requirements), then calculate monthly ?Storage/Supplemental Municipal Water Requirement.?

Calculate Supply.
The following equation calculates amount of water (in gallons) that can be harvested from a catchment.

Follow these steps to use the equation:

Sample Supply Worksheet
Blank Supply Worksheet

? Multiply rainfall in inches by 0.623 to convert inches to gallons per square foot.
? Multiply the result by the area of catchment in square feet (ft2). (For example, a 10 foot x 20 foot roof is 200 ft2. For a sloped roof, measure the area covered by the entire roof, usually the length times the width of the building.)
? Multiply this result by the run-off coefficient to obtain the available supply. (The run-off coefficient is the percentage of total rainfall that can be harvested from a particular surface. The higher the run-off coefficient, the less absorbent the the surface.)

Calculate Demand.
The demand equation calculates the amount of water a particular landscaped area needs. (HELPFUL HINT: To make water demand calculations easier, group together new landscape plants with similar water requirements. Such grouping also makes it easier to manage irrigation zones.)

Follow these steps to use the equation:

Sample Demand Worksheet
Blank Demand Worksheet

? Determine the monthly reference evapotranspiration (ET) in inches for your area.
? Multiply ET by the plant water use coefficient, representing the percent-age of reference ET a particular plant needs.
? Multiply the result by 0.623 to convert inches to gallons per square foot.
? Multiply this result by the size of the irrigated area in square feet. (Irrigated area refers to how much area is planted. Do not include unplanted portions of the landscape in your calculations.)

Once Susana has calculated supply and demand for each month, she can determine her system?s maximum storage needs. Although containers of any size will reduce Susana?s dependence on municipal water, to take full advantage of available rainfall she should build enough storage to meet total irrigation water needs.

Calculate Maximum Storage/Supplemental Water Use.
Once you have calculated how much rainfall you can potentially harvest and how much irrigation water you need, use a ?checkbook? method to determine monthly harvested water balance and amount of supplemental water (municipal or from another source) needed to meet any shortfalls. The calculations in the use the scenario from Examples 1 and 2. To keep things simple, calculations are performed on a monthly basis, although the amount of available water changes daily.

"Cumulative Storage? refers to available water.
To determine the current month?s cumulative storage, add the previous month?s cumulative storage to the current month?s yield, then subtract the current month?s demand from that total. If the remainder is positive, place it in the Cumulative Storage column for the current month. If the remainder is negative (that is, if irrigation demand is greater than stored water supply), place it in the Supplemental Water Use column to indicate the amount of supplemental water needed for that month.

Balancing Supply and Demand.
In this scenario, during the summer Susana?s landscape demand always requires a supplemental water supply. But during the winter months, rainwater supply exceeds demand due to low evapotranspiration rates, so water can be saved for spring and early summer water deficit periods.

Every site generates unique supplies and demands.
For some sites, rainwater harvesting systems always provide enough water to meet irrigation demands, while for others, harvesting can only partially satisfy such demands. Remember that supply fluctuates from year to year, depending on the weather (when and how much it rains). Demand can increase with warmer-than-normal weather, as the landscape ages and plants grow larger, and while new plants get established.

If supplies of harvested water do not meet irrigation demands, balance your water harvesting checkbook either by increasing supply or by reducing demand.

To increase supply:

? Increase your catchment?s area or run-off coefficient.
? Use another source of water, such as your municipal supply.

To reduce demand:

? Reduce landscaped area.
? Reduce plant density.
? Replace high-water-use plants with lower-water-use plants.
? Use mulch to reduce surface evaporation.

Step #3. Final design and construction.

Catchments and Landscaping.
Use your site analysis and your supply and demand calculations to determine size and location for catchment areas. Use gutters and downspouts to carry water from a roof catchment to your storage areas. Design or retrofit roofs or shade structures to maximize your catchment area. If you cannot provide a catchment large enough to meet maximum landscape water requirements:

? For existing landscapes, reduce plant water demand either by lowering plant density or by selecting lower-water-use plants.
? For new landscapes, select types and numbers of plants that can be supported by the water harvested from your existing catchment.

To use harvested water most efficiently, group together plants with similar water needs. And remember that new plantings, even of native plants, need increased amounts of irrigation during their establishment period, which can range from 1 to 3 years. (Use supply and demand calculations to determine the amount of water needed for new plantings.)

Storage Containers and Distribution.
Use storage containers large enough to hold your calculated supply. Place containers close to plants and, to take advantage of gravity flow, higher than planted areas. Use pipes, hoses, channels and drip systems to distribute water. For drip systems and those without gravity flow, use a small pump to move water through the lines. Select drip irrigation filters with 200-mesh screens and clean them regularly.

Step #4. Field testing.

Once you?ve built your water harvesting system, ?field test? it during rains. Determine whether water is moving where you want it to go or whether some of it is being lost. Determine if holding areas adequately contain water. Make changes to your system as required.
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Rainwater as a Drinking Water Source

Single Households

From a regulatory perspective, the Texas Commission on Environmental Quality (TCEQ) has rules that only apply to a rainwater system that supplies potable water for a public water system or for any business that manufactures food or beverages. TCEQ does not set minimum treatment requirements for rainwater that will be used as a drinking water source for a single household nor do they regulate nonpotable uses of rainwater.

Harvesting, Storing and Treating Rainwater for Domestic Use (GI-366) will help you design and operate a roof-based rainwater harvesting system to supply drinking water for you and your household. The publication focuses on the information you need to make sure that your system will produce water that is chemically and biologically safe to drink.

Public Water Systems

To assure that the water produced by a public water system is chemically and biologically safe to drink, the TCEQ has adopted regulations regarding the design, operation, and maintenance of public water systems and the quality of the water they produce. A public water system is defined as any system that serves at least 25 people per day for at least 60 days each year or that serves at least 15 service connections.

Rainwater Harvesting: Guidance for Public Water Systems (RG-445) is a guide for public water systems that collect and treat rainwater and distribute it as potable water. It offers a general overview of the TCEQ rules that apply to public water systems that use rainwater as a drinking water source and to systems that use it as a source for a commercial bottling operation.
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System Maintenance

Developing a water harvesting system is actually an ongoing process to be improved and expanded over time. For example, you may discover additional areas where water can be harvested or channeled. Inspect your water harvesting system before each rainy season (and, ideally, after every rainfall) to keep the system operating optimally.

Use this maintenance checklist to keep your system in top condition:

? Keep debris out of holding areas.
? Control and prevent erosion; block erosion trails.
? Clean and repair channels.
? Clean and repair dikes, berms and moats.
? Keep debris out of gutters and downspouts.
? Flush debris from storage container bottoms.
? Clean and maintain filters, especially those on drip irrigation systems.
? Expand watering basins as plants grow.

Once your system is operating, monitor landscape water use to find out the amount of water saved. For new water harvesting basins in existing landscapes, compare previous years? (pre-harvesting) water bills with post-harvesting figures. When new plants are added to a water harvesting area, water savings begin as soon as they are planted and continue for as long as you irrigate with harvested rainwater.

http://rainwaterharvesting.tamu.edu/

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MORE RAINWATER HARVESTING SITES:

http://rainwaterharvesting.tamu.edu/Rainwater_Harvesting_Presentation_files/frame.htm

http://www.oasisdesign.net/water/rainharvesting/index.htm

http://dmoz.org/Science/Environment/Water_Resources/Rainwater_Harvesting/

[Jonesie]

UK: RAINWATER HARVESTING

RAIN HARVESTING SYSTEMS COMPANY
Founder member of The UK Rainwater Harvesting Association
website:

http://www.rainharvesting.co.uk/

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UK Rainwater Harvesting Association
website:

http://www.ukrha.org/index.php

The concept of capturing rainwater and storing it for later use is well documented from pre-Roman times and on all the major continents, although in industrialised countries, until recently, the practice had largely died away with the introduction of reliable mains-supplied water. With the ever-growing demand for water (and subsequent increases in cost), and the known adverse impacts this can have on local environments, the UK market demand for rainwater recycling systems is on the increase - mirroring what has already taken place in other industrialised countries.

Currently, this relatively new industry (insofar as the UK is concerned) is at an embryonic stage and needs to work together to ensure that its benefits are brought to as wide a market as possible. In so doing, the reputation of the industry and its products needs to be safeguarded in the interests of all parties and, in particular, the environment.

The UK Rainwater Harvesting Association has been launched to address this need.

1.What happens in a dry spell?

When there is insufficient water in the storage tank the system automatically draws water from the mains again, so that from the point of view of the user no difference is apparent.

2.Is the water clean?

The tanks have filters that remove all debris and particles from the water, so that the water remains clear.

3.How much water is saved?

This depends on the size of your catchment area (usually the roof of the building) and the amount of rainfall in your area. Independently monitored typical domestic installations show that close to all non-potable household requirements were met, saving around 50% on mains water consumption.

4.What is the payback period?

This also varies depending on the amount of rainwater you collect and the cost of water in your area. This can be as low as 2-5 years for commercial systems and between 10-15 years for domestic systems.

5.Why should I buy one?

Because the system will generate significant environmental benefits through reducing mains water demand and reducing storm water run-off. In addition with water bills expected to rise 10% a year for the next five years then the payback period will be reduced further. Also, control of storm-water run-off is now increasingly a Planning issue which rainwater harvesting systems can play an important part in addressing.

6.What can I use the water for?

The water harvested is suitable for all non-potable purposes from watering the garden (rainwater is, unsurprisingly, particularly beneficial to plants), washing the car, flushing the toilet and running the washing machine. In certain cases it may be possible to achieve potable water standard through additional treatment.

7.Is it only for new buildings?

Systems are best designed-in from the outset, but can be retrofitted depending upon the accessibility of pipe work. We would like to see the Government legislate to ensure that all new structures are built with separate potable and non-potable pipe work, thereby making subsequent retrofitting a very straightforward proposition

8.What happens when it breaks down?

All systems are designed with reliability at the forefront and experience shows that this pays dividends in terms of extremely low failure rates. The systems are also designed to be easily and speedily rectified when the need arises.

9.Is there a danger of Legionella?

No, the system does not provide the conditions necessary for the cultivation of Legionella. With the water stored underground it is dark cool and is kept well oxygenated. Legionella cannot cultivate in these conditions.

10.How much does it cost to run the pump?

It typically takes 1.5- 2.0 kWh to pump 1 cubic meter of water (1000 litres). For a typical house using rainwater for WCs, washing machine and the garden, pumping costs are between 5-10p per week.

11.How big is the system/storage tank?

Varies, and is matched to the catchment capability of the roof, and the likely consumption of non-potable water in the building

12.How much does a system cost?

Between ?2000 and ?3000 for a good quality domestic system depending on the size. Industrial systems can be much more expensive but will deliver bigger savings because of increased roof areas.

13.Do Building Regulations affect/require the installation of a system?

They are not required directly by Building Regulations, although they may be linked with the Planning Permission for the storm-water management of the site. Building Regulations do cover the installation itself, tank siting & pipe runs etc

14.How do I design a system?

Best left to the supplier working in conjunction with the Specifier.

15.What maintenance is required?

Varies from system to system, but invariably minimal; typically, washing off the filter ( 5-minute job with a garden hose) once a quarter is all that is required.

16.Can I drink the water?

Additional UV filtration can be added to bring up to potable standard if this is a requirement.

17.How long will a system last?

The buried components, indefinitely; components such as the control system, pump and filter have an extremely long working life, and are easy to replace should the need arise.

18.How big is the market for rainwater harvesting in the UK?

Currently, around 400 systems are installed each year.

19.How big is the potential UK market?

This will depend upon a number of factors, including Government policy & legislation, practical issues associated with water-supplies and management, and consumer demand.

20.How big is the market on the continent?

The industry on the continent is approaching the installation of 100,000 units per year.

21.How old is the technology?

The technology and principles of rainwater harvesting have been around since pre-Roman times, however the modern systems date back to Germany in the mid 1980?s.

22.Can I get any grants or tax allowances for installing a system?

At present there are no funding directly aimed at rainwater harvesting. It does however qualify for 100% capital allowance relief on commercial premises.

23.Is it a proven technology?

Yes it is. Systems have been installed in Germany since the early 1980's. One benefit of the UK market being generally ?behind? the rest of Europe is that the potential problems have been worked through and solved, especially by the extensive work taken place in Germany.

24.How will it affect my domestic appliances?

If you are in a hard water area and install a rainwater harvesting system, white goods, such as your washing machine, often last longer and run more efficiently. Harvested rainwater is soft and so the machine will not build up internal limescale and shorten its lifespan. An additional benefit in hard water areas is that less detergent is required which means less pollutants released into the environment.

25.Will a system change my homes eco-rating?

Yes, rainwater harvesting is an important ER criterion. The EcoHomes rating system addresses all aspects of reducing potable water demand in a dwelling. Installing a rainwater harvesting system adds to the credit rating for water use.

26.What do water companies think about rainwater harvesting?

Whilst it is not for UKRHA to speak for the UK water industry as a whole, generally we find the water supply companies to be co-operative. One important benefit for the UK?s water industry may be in reducing the cost of future investment in new storage of scarce water resources, and the associated environmental impacts.

27.What is Sustainable Urban Drainage (SUDS)?

Sustainable Drainage Systems (SUDS) offer an alternative approach to the drainage of developed areas which takes into account water quality, flood risk and amenity. The result is an integrated approach to drainage which minimises environment impact. Rainwater harvesting systems are recognized as one part of a SUDS system.

28. How often does a system overflow?

In a well designed RWH system the tank will overflow two or three times a year. This is important as it removes any floating sediment and recharges the trap that prevents drain smells entering the tank.

29.How often does a system need topping up?

A well designed system with a good match between supply and demand will only need topping up when it has not rained for some time. Severn Trent monitored a domestic system and found that the only occasionally needed to be topped-up. Most of the time the tank was around 50% full (i.e. an ideal balance between having plenty of water to use, and plenty of space to accommodate the next rainfall).

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The Answer to Water Shortages

The water-shortages widely reported currently in the national press echo the earlier warnings of the Rt Hon Elliot Morley MP, Minister of State for Climate Change & Environment, who recently stated that both time and water are running out ? and we have to act now.

A proven, cost-effective way of addressing this particular problem is through the use of rainwater-harvesting systems. Once widespread throughout the UK, such systems fell out of fashion with the introduction of mains water supplies. They are now experiencing a renaissance in this country which has seen a tripling of the market over the last two-years.

A rainwater harvesting system, collects water that falls onto the roof of a property for subsequent use in non-potable applications, such as toilet flushing, clothes washing machines, car washing and garden watering. Typically, independent trials have shown that a domestic rainwater harvesting system reduces mains-water consumption by around 50%.

The systems are also extremely cost-effective when used on commercial and public buildings where there is a combination of large roof area and a high consumption of non-drinking water for toilet-flushing or commercial processes. Fleet-washing at distribution centres, for example, is a costly process that wastes mains water which has been purified to an un-necessarily high standard. Using harvested rainwater instead therefore makes excellent commercial and environmental sense.

When light rain falls, much of the water is re-absorbed into the atmosphere, rather than finding its way into the water table or reservoir system. A rainwater harvesting system, however, intercepts this water conserving it for subsequent use. Conversely, during heavy downpours, rainwater harvesting systems help to alleviate flood-risks by easing flows into the storm-water management grid, minimising waste and disruption. Use of harvested rainwater for non-potable applications also saves the energy that would otherwise be wasted in bringing water un-necessarily up to mains, drinking water standard.

As the world faces the pressure of climate change and water shortages, we can expect to see an increase in the use of rainwater harvesting. This is reflected in the year-on-year growth in the UK for systems which currently approaches 100%.
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RAINWATER HARVESTING ?SNIPPETS?


? the use of rainwater harvesting in Germany, is c100 times the current use in the UK ?

? the UK market for rainwater harvesting has increased by around 300% in the last 2-years ?

? a typical domestic rainwater harvesting system provides around 50% of a household?s total consumption?

? the payback period on systems for buildings with large roofs and high non-potable water demand is c3-years ?

? the roof on a typical 4-bed family home captures more than 100,000 litres of water each year ?

? a typical family uses 70,000 litres each year on toilet-flushing, clothes washing & outside use ?


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UK-RHA Surveys Indicate 50% Growth of the Industry

UK-RHA member surveys indicate that the UK rainwater harvesting industry has grown around 50% over the last 12-months as Government, Planning Authorities and Developers increasingly see the environmental and commercial case for making better use of an increasingly scarce resource.

Government?s stated housing development plans for an already water-constrained south-east, coupled with its ?sustainable communities? policies is throwing increased emphasis on the use of harvested rainwater to reduce demand on mains water, to help manage development storm-water management, and to save on the energy used in producing potable water.

Background notes on all these issues are to be found in the Downloads section of this site.

http://www.ukrha.org/content.php?t=11&page=news

[Jonesie]

CISTERNS

Cistern
From Wikipedia, the free encyclopedia


Getting water out of a cistern
A cistern (Middle English cisterne, from Latin cisterna, from cista, box, from Greek kist?, basket) is a receptacle for holding liquids, usually water. Often cisterns are built to catch and store rainwater. They range in capacity from a few litres to thousands of cubic metres (effectively covered reservoirs).


Creating and using cisterns

Cisterns are built by digging a hole in the ground to form a tank, with a single opening in the top to allow access. The walls of a cistern must be watertight in order to retain moisture. In the early 1900s cisterns were often made with a cement floor and dirt walls that had been coated in plaster. Modern-day cisterns may also be made from above-ground tanks, made of plastic. Cisterns usually have a lid covering their openings to prevent dirt, animals, insects, and other things from getting into the water.

Cisterns are commonly used in areas where water is scarce, either because it is rare or because it has been depleted due to heavy use. Early on the water was used for many purposes, including cooking, irrigation, and washing.

Present day cisterns are often only used for irrigation, due to concerns over water quality. Cisterns today can also be outfitted with filters or other water purification methods when the water is meant for consumption. A few people leave their cisterns open to catch rain, or have more elaborate rain-catching systems. It is recommended in these cases to have a system that does not leave the water open to mosquitoes or algae, which are attracted to the water and then carry disease to nearby humans.

Some cisterns sit on the top of houses or on the ground higher than the house, and supply the running water needs for the house. They are often supplied not by rainwater harvesting, but by wells with electric pumps, or are filled by manual labor or by truck delivery. Very common throughout Brazil, for instance, they were traditionally made of concrete walls (much like the houses, themselves), with a similar concrete top (about 5 cm. thick), with a piece that can come out for water filling and be re-inserted to keep out debris and insects. Modern cisterns are manufactured of plastic (in Brazil with a characteristic bright blue color, round, in capacities of about 10k and 50k liters). These cisterns differ from water tanks in the sense that they are not completely enclosed and sealed with one form, and rather they have a lid made of the same material as the cistern, which is removable by the user.

To keep a clean water supply, the cisterns must be kept clean. It is recommended to inspect them regularly, keep them well-enclosed, and to occasionally empty them and clean them with an appropriate dilution of chlorine and to rinse them well. Well water must be inspected for contaminants coming from the ground source. City water has up to 1ppm (parts per million) chlorine added to the water to keep it clean, and in many areas can be ordered to be delivered directly to the cistern by truck (a typical price in Brazil is BRL$50, USD$20 for 10k liters). If there is any question about the water supply at any point (source to tap), then the cistern water should not be used for drinking or cooking. If it is of acceptable quality and consistency, then it can be used for (1) toilets, and housecleaning; (2) showers and handwashing; (3) washing dishes, with appropriate sanitation methods, and for the highest quality, (4) cooking and drinking (5)Irrigation. If it is free of particulates but not low enough in bacteria, then boiling may also be an effective means to prepare the water for drinking.

Many greenhouses use cisterns to help meet their water needs, especially in the USA. Some countries or regions, such as Bermuda and the U.S. Virgin Islands have laws that require rainwater harvesting systems to be built alongside any new construction, and cisterns can be used in these cases. Other countries, such as Japan, Germany and Spain, also offer financial incentives or tax credit for installing cisterns.

http://en.wikipedia.org/wiki/Cistern

[Jonesie]

THE HOMESTEAD CISTERN

THE HOMESTEAD CISTERN

Collecting and storing rainwater for homestead use.

Whether your well has just gone dry and you need a new (and preferably low-cost) source of water . . . or that sprig you've been drawing from doesn't always produce as much as you (or your animals) would like . . . or you've grown tired of the taste of city water . . . you'll want to see what Penny and Lou Kujawinski (authors of the following article) have to say about collecting and storing rainwater for homestead use.


Have you ever looked at a pretty piece of land but hesitated to buy the property because it lacked water? (Quite often, an otherwise-attractive parcel of land that has no well, pond, stream, or spring will be priced so low that you may be tempted to buy the tract anyway.) Lack of ground water is a common problem . . . one that the folks in our part of Missouri?early settlers and present-day farmers alike?have learned to get around by the use of something known as a rainwater cistern .

A rainwater cistern is?as the name implies?simply a setup for collecting rainwater (usually the precipitation that falls on your home's or barn's roof) and storing it until it's needed in a (usually underground) concrete or masonry tank. Cisterns are ideal for farms and homesteads situated on waterless land, or for areas where the natural ground water is too hard?contains too many dissolved minerals?to drink, use for washing hair, etc. (Fact is, some of the people hereabouts who have good springs on their property have gone ahead and installed cisterns anyway, just because they prefer the taste of rainwater.)

We didn't feel out of place, then?upon moving to our present home?when we designed and constructed a simple rainwater-collection system large enough to supply all our needs for water. And?despite the limitations inherent in such a system?we've never regretted having gone this route. (It sure beats spending upwards of $1,000 to drill a well for water that may or may not be there!) Quite possibly, a cistern could be the answer to your water-supply problems, too.


HOW TO KNOW WHETHER A CISTERN IS "RIGHT" FOR YOU

Cisterns won't work for everybody. In fact, for such a setup to be at all useful, the following conditions must apply:

[1] You must live in an area that gets plenty of rain. As a general rule, you can figure that if crops can be grown without irrigation where you live, there'll probably be enough precipitation to meet your water needs. (In times of drought, you can do what we do: Have water hauled in, at a cost of about $10 per 1,000 gallons.)

[2] The rainwater collection surface?usually a house or barn roof?should not be located near (or downwind of) any source of pollution (such as a major highway, fields or orchards where spraying occurs, or factory smokestacks).

[3] Your water needs must not be excessive. (For those of us who prefer a dry toilet to the kind that wastes up to seven gallons of H 2 0 with every flush, this requirement shouldn't pose much of a problem.) Of course, if you're thinking of building a cistern to supplement your present well, spring, etc., this factor becomes less important. The main thing to remember is that if?like the average American family?you use 100 gallons of water per person per day . . . you're either going to have to cut down on that consumption, or build a cistern large enough to fulfill your needs (which?depending on the amount and frequency of rainfall in your area?could mean a tank of 5,000 to 10,000 gallons' capacity, or larger).


UNDERGROUND OR ABOVEGROUND?

Cisterns can be built above- or below-ground. The advantage of an aboveground installation is that the weight of the water itself (as long as the storage tank is above faucet-level) can be harnessed to pressurize your home's waterlines . . . whereas with an underground cistern, it's necessary to pump the water from the storage vessel to the house. On the other hand, with an underground cistern [1] the water remains cooler in the summer (resulting in less evaporative loss), and [2] there's no danger of the liquid freezing in winter. We chose to build our cistern underground for these reasons.


HOW MUCH WILL IT COST?

Cisterns can vary widely in cost, depending on how fancy you want to get and how much of the installation you do yourself. Our system?which centers around a 13'-deep, 1,100-gallon storage tank built of fieldstone and mortar?set us back a total of about $100 . . . for everything, including gutters, cement, pipes, and an old-style manual pitcher pump. By contrast, some neighbors of ours spent approximately $1,000 to have a contractor install a pre-cast concrete cistern with an electric pump and an automatic chlorinator. As you can see, then, exactly how much you spend on a cistern installation depends largely on what you have more of: time or money.


THE CISTERN'S COMPONENTS

All cistern setups can be divided into three components: [1] the water collection system (roof, gutter, and downspout), [2] the filter, and [3] the water storage vessel (or cistern).

A very important thing to keep in mind about your cistern's water collector is that the collection surface (the house or barn roof, in most cases) must be free of any material(s) which might pollute the water it catches. (A painted surface isn't suitable, since chips of the protective coating will inevitably wash down into the storage tank.)

To aid in keeping their collected water clean, most cistern owners install a "shut-off" (or short length of movable pipe) in their systems' downspouts. Then, during the first few minutes of a rain?when all the soot, bird droppings, etc., that have accumulated on the roof's surface begin to wash away?the runoff can be diverted away from the cistern. (This tainted water can be shunted to the garden or used in any way you'd use "gray water".) Shortly afterwards?when it has rained a few minutes and the water flowing through the downspout appears clear and clean?the shut-off can be switched back to direct the remaining portion of the shower or storm into the cistern.

The filter mentioned above is usually nothing more than a concrete enclosure (see diagram) that's divided into two sections by a partition reaching two-thirds of the way to the chamber's top. One of the two sections is left empty, while the other is layered full of filtering material(s) . . . usually gravel, fine sand, and/or activated charcoal. The idea is that as water flows from the downspout to the first (i.e., empty) section of the "filter box", bits of leaves, dirt, etc., will settle out . . . then?as the collected liquid spills over the partition and begins to percolate down through the layers of filtering material?smaller impurities also will be removed. A screen prevents any remaining debris from flowing into the supply line that connects the filter box with the cistern.

The cistern itself should be made of concrete, stone, or some other non-corroding, non-contaminating material (wood and metal are not recommended). In addition, the storage tank must be [1] watertight, [2] effectively sealed against outside contamination, and [3] fitted with some type of overflow opening. For optimal protection against contamination, the cistern's hatch door should fit tightly, the overflow should be screened to prevent small animals from entering, and care should be taken to locate outhouses, septic tanks, cattle run-off areas, etc., at least 100 feet away (preferably downhill ) from the tank. (Note: Your cistern most definitely should have a hatch door on its top, since the vessel's floor will need to be cleaned every couple of years or so.)

Although we don't necessarily recommend the use of such poisons, chlorine and other chemical disinfectants can be added to your cistern?either manually or by means of an automatic dispenser?from time to time to ensure the sterility of your water supply. [EDITOR'S NOTE: Some commercially available water disinfection units rely on heat or ultraviolet light?rather than chemicals?to get the job done. Look in the Yellow Pages of your phone book under "Water Purification Equipment" or "Water Supply Systems".] You may want to consult the local health authorities?or your county agricultural extension office?about whether or not you should disinfect your cistern's water.


THE PUMP

Unless your cistern is situated above faucet-level, you'll need a pump to force the water out of it. Here?as with wells?you can choose from any number of kinds of devices (some expensive, some not) to do the job. For simplicity and low cost, we installed a hand-operated piston pump atop our cistern . . . and it works quite well. If you decide to go this route, remember that a piston pump can only draw water a maximum of 25 feet from the source. (Which means you should build your cistern close to the house if you intend to use an indoor hand pump to empty it.)


THE KUJAWINSKI SYSTEM

Our own system?though it works well enough for our needs?bears the marks of a first-time do-it-yourselfer and could stand some upgrading in certain areas. For instance, our water collection surface (a 24' X 24' cabin roof) should really be somewhat bigger to furnish us with a truly adequate water supply. (As it is, it takes a 5" rainfall to bring our cistern up to the 600-gallon mark.) Then too, the underground tank could've been a little larger . . . but digging through the hardpan clay we have in this area is no easy chore.

I might add that although fieldstone is inexpensive and abundant, it was not the best possible choice of construction material for our holding tank, since [1] the stones in our area are of odd sizes and shapes (rarely square or flat) and [2] the process of fitting each rock in place individually was excruciatingly slow and fatiguing. A small additional outlay for the extra cement and gravel that would've been necessary to do the whole job in concrete would have made life a lot easier . . . and construction a great deal speedier. (The cistern's reinforced-concrete top was certainly easy enough to fabricate.) Now that the job is finished, though, I suppose our only real regret is that the beauty of the cistern's stone walls cannot be seen from above.

One part of our system that we're particularly pleased with (especially considering that its dimensions were arrived at mostly by guesswork) is the water filter (a trapezoidal concrete box divided into a 2' X 3' X 1'-deep "main section" and a smaller, triangular section with 18"-long sides). So far, we haven't had a chance to try sand, charcoal, and gravel in combination . . . instead, we've had to rely just upon pea gravel and metal screening as filtering agents. (The screening is installed below the gravel as well as atop the filter box's partition wall.) Nonetheless, we're quite happy with the clean water that our filter produces.



DO SOME DIGGING BEFORE YOU BEGIN

If I had just one piece of advice to give to someone who's interested in installing a rainwater cistern, it'd be this: Do your homework before you begin. Check with your state health department and the state department of agriculture for literature on the subject of cisterns and water systems. Also, talk to your county agent . . . he may be able to suggest (or even give you) helpful bulletins, reprints, etc. A trip to the library could also prove beneficial.

Unfortunately, you won't find detailed discussions of cisterns in many of the popular books on homesteading. Two guides that do cover cisterns in some depth are:
[1] the American Association for Vocational Instructional Materials' Planning for an Individual Water System (available for $7.55 postpaid from AAVIM, 120 Engineering Center, Athens, Ga. 30602), and
[2] Volunteers in Technical Assistance's Using Water Resources (available for $5.00 plus 95? shipping and handling from Mother's Bookshelf, P.O. Box 70, Hendersonville, N.C. 28739).

Do a little digging and you just may find that a lack of ground water doesn't have to keep you from purchasing that much-wanted patch of land in the country. Not if you're willing?like us?to drink (and bathe in) a little rainwater now and then.

http://www.motherearthnews.com/Homesteading-and-Self-Reliance/1978-05-01/The-Homestead-Cistern.aspx

http://www.motherearthnews.com/gallery.aspx?id=66244

[Jonesie]

WATER TANKS - ABOVE GROUND

Here are a lot of sites selling water storage tanks. I don't represent any of these companies, I am just posting them to give you an idea of the various methods of storing water. There are wide price differences for the identical products, and shipping can be exhorbitant.
So check your yellow pages for barrels, drums and cisterns in your immediate area.
If you are planning on buying a storage tank and keeping it in an apartment or house, you must take into consideration the weight of the tank when filled. 1 gallon of water equals 8.33 lbs. A filled 55 gallon water barrel will weigh around 450 pounds. You do not want to damage the floor with too much weight. Too many water barrels in one room could lead to a big problem. .

WATER TANKS:

http://www.ntotank.com/

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LOW PROFILE WATER TANKS

The 1250 low profile tank may be used for storage or transport. They are an excellent choice when height limitations are a factor and are the perfect height for putting under your cottage or cabin.

http://www.plastic-mart.com/class.php?item=9

http://www.plastic-mart.com/products.htm

--------------------------

http://www.urbangardencenter.com/products/rainbarrel/urb/index.html

WOOD:

http://www.forestlumber.com/cistern.php

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VINYL CLOSED:

http://www.plastictanks.ca/category.php?cat_id=101

http://www.plastictanks.ca/category.php?cat_id=102

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TRACTOR SUPPLY STORES:

http://www.mytscstore.com/detail.asp?pcID=4&paID=1034&sonID=157&page=1&productID=16775

http://www.mytscstore.com/detail.asp?pcID=4&paID=1034&sonID=157&page=1&productID=16777

If you have a swimming pool, think of a method of running rainwater from a roof into the pool, should your municipal water system fail. An above ground pool may be a more economical way of storing water than purchasing a cistern, but it would need to be kept covered at all times. And you need gallons of chlorine for swimming pools.

[Jonesie]

Re: RAINWATER HARVESTING

Rainwater Harvesting and Purification System

In January 1996 we installed a rainwater catchment system to capture Oregon's abundant rainfall. Portland receives between 3 and 4 feet of rainfall annually. During a gentle rain a typical Oregon downspout sheds several gallons per minute. Our twelve hundred square foot roof captures on average 3600 cubic feet (27,000 gallons) of water per year.

In 1998 we received approval from the city of Portland to use this water for all household use. This system, which cost less than $1,500, consists of the following components:

• A 1500 gallon plastic cistern, approximate cost: $500. Purchased from Northwest Irrigation, Tangent, Oregon, 541-928-0114. Contact local agriculture/farm stores for best prices.
• A 1/2 horsepower shallow-well pump to pressurize the water to between 20 and 30 psi (pressure is adjustable), approximate cost: $250. I utilized a Jaccuzzi brand pump.
• Plastic (outdoor PVC and indoor CPVC) piping to connect to the household cold water system.
• Two particulate filters in series, rated at 20 and 5 micron particle size, approximate cost: $20 each; replaceable filter cartridges cost $3-5 each.
• An ultraviolet light sterilizer capable of sterilizing water at 10 gallons per minute. This appliance was recently approved for use in Oregon. I used the PURA (1-800-292-PURA, Valencia, California) model UV20-1, cost approximately $350. Uses about 40 watts. Fluorescent ultraviolet light rated at 9600 hours, about one year of continuous use. Replacement cost of fluorescent tube: about $80.
• Screen covering the cistern to prevent entry of mosquitoes and to catch any large particles that make it past the gutter screening.
• A roof-washer which wastes the first 7.5 gallons of captured water which has "washed" the roof. Once the roof washer has filled, the rest of the water flows to the cistern. See below for details.
• A 20 gallon water butyl rubber diaphragm pressure storage tank, approximate cost: $150.
• A reduced pressure backflow prevention device. This was required by the city to prevent flow of rainwater into the public system. Cost: $120. This would not be necessary if we used rainwater exclusively. However, Oregon has very dry summers and our cistern is exhausted by July. We currently depend on city water during the summer. The city requires annual inspection of these devices, costing about $30. (See photo below.)
• A (optional) water meter to measure rainwater output, approximate cost: $45.

Maintenance consists of keeping gutters and cistern screen clean. Filters and ultra-violet lamp will need periodic replacement. The tank is thoroughly cleaned annually in the summer when it empties. Backflow prevention device requires annual inspection. Public health authorities recommend periodic testing of water for fecal coliform bacteria, as for any private water system. Several recent tests showed none. The inside components of our system, pictured here, take up about 6 square feet of floor space.

At the current time we continue to use the public water supply only for summertime water and occasional drinking and cooking. In fact, during the rainy season, which lasts from about September to June, our only connection to the public utility is one faucet at the kitchen sink which uses less than one gallon per day, which got us into hot water with the city water bureau.

In my research on rainwater catchment systems the best single reference I have come across for detailed design guidelines is the Texas Water Development Board's Texas Guide to Rainwater Harvesting.

Roofwashers.
A simple prototype is shown in the TG. It consists of a length of pipe for storage of the initial flush of water with a trickle valve (hose bib just slightly opened) and clean out valve at the bottom. Only when the this pipe fills is water then allowed to continue into the cistern. It's very simple, no moving parts. The only thing I would change is to have a narrow section or trap configuration at the top to reduce mixing of the flush water with the still arriving (clean) water. Yet another method to aid this is to add a lightweight (like styrofoam) ball that would seal the intake when the roof washer fills. This simple design is very inexpensive, easy to drain or clean manually, and works very well. The TG suggests one gallon of washer capacity for each 100 square feet of roof. So make your roof washer pipe length long enough. For our model we used 20 feet of 3" ABS. We made it in the shape of a giant U to get this length. Remember, volume equals length times area. Area equals pi times radius squared (in our case 3 inches internal diameter, or .25 foot) and one cubic foot equals 7.5 gallons. To avoid long lengths of roofwasher pipe, it makes sense to use larger diameters. Portland's chief residential plumbing inspector commented that our use of ABS didn't conform to code as plastic may eventually decay in sunlight. Therefore, you should use copper, iron, or other sunlight-resistant materials to be completely correct.

Rainbarrels.
A rainwater harvesting system can be as simple as a barrel connected to a downspout. Check the Rainbarrel Tutorial for tips on how to put together a system for as little as $15-20. One of our neighbors has connected his rainbarrel to his basement washing machine and gets virtually all his laundry water from this super-soft source for a miniscule investment.

One notable advantage of rainwater is its softness. Rainfall in the Portland area contains about 5 mg/liter of dissolved minerals. Compare this with some hard groundwater which exceeds 500 mg/liter. Portland city water, which has an exceptionally pure source, is rated at 18 mg/liter.

According to two officials in Alaska and Hawaii with whom I have communicated, there is a long established tradition of rainwater collection in some parts of their states. According to Sourcebook Harvested Rainwater, in some areas of the Caribbean, new houses are required to have rainwater capture systems. Hawaii apparently is currently developing (or has already developed) guidelines. In Oregon, there is no regulation of water quality for individual residences -- this is left up to the homeowner. The only regulations I have come across relating to rainwater harvesting are from Ohio, whose Department of Health Administrative Code regulates private water systems. Note, in particular, Rules 3701-28-09 Continuous disinfection and 3701-28-13 Construction and surface design of cisterns, hauled water storage tanks, and roof washers.

Two other great resources for rainwater harvesting information are Warwick (Coventry, United Kingdom) University's Development Technology Unit Roofwater Harvesting Programme and the roofwater harvesting listserve archives.

Update Summer 2002 -- A different style of roof washer. This summer we installed a commercially available roof washer that uses a programmable valve to divert a rain's first flow away from the cistern. A purported advantage is the absence of standing water that can stagnate and potentially contaminate the cistern water. (This could happen, for example, if the trickle valve on the conventional device were to clog or it were left closed.) Below are two photos of the system with this new device. The first photo shows the roof washer mounted on a window frame near the cistern. Rainwater, which enters from the two downspouts above, can be observed from inside the dwelling. The first flush is diverted downwards into a holding barrel. An overflow hose from the top of the cistern also empties into this barrel. Post-flush water enters the cistern via the roof washer's side port through a screened cistern entry hole. The barrel overflow is directed to a swale in the middle of our back yard.


Update January 2004 -- An American-made roof washer and rainwater sculpture. I never was able to get the SafeRain roof washer to function properly in Oregon's often drizzly weather. Either the roof washer diversion valve would not properly close, thus diverting all the rainwater into the overflow, or it would not open after the rainfall event ended, retaining dirty water in the device. I attempted numerous times to adjust it, all to no avail. Unfortunately, for this reason, I can not recommend this device. The last straw came during recent freezing weather when the device froze with water in it, rendering it non-functional. Therefore, recently, I installed a newer style of first-flush device. This device is considerably less expensive (approximately $66 versus $140 at currency exchange rates 22 Jan 2004, including shipping) for North Americans, since it is locally made and uses standard pipe fittings. The first-flush valve kit consists of a hollow ball (see middle two photos below) which, when filled by the initial flow of water, seats itself onto a rubber gasket. This closes the overflow pipe and subsequent rainwater is then diverted to the cistern. After the rain stops the ball empties and the diversion valve returns to the open position. I will post a review of how well this device performs at the end of this rainy season. At this time it already seems to be functioning properly.


At the same time I installed this roof washer I also installed a more elaborate piping configuration (see photo, above, left) leading from the downspouts to the cistern that is intended to act as a water sculpture. Viewable from our dining room window, it will display ten areas of flowing water, depending on the time in a rainwater event and the rainwater flow. During a typical Oregon drizzle, only the left most vertical pipe (see photo, above right) carries water. During a downpour all three pipes will be filled to capacity and additional flow will emerge from the 2" elbow.

Update January 2005-- final roof washer review. Unfortunately, this second roof washer employs the same mechanism as the earlier, Australian, model to reset itself after a storm event. Both devices use a small, hollow, plastic ball that fills with water when rain begins. While the ball fills, the initial dirty rainwater is wasted. When the ball is full, it lowers over a drain hole, causing the remaining clean rainwater to be diverted into the cistern. The problem with both these devices is that their ball depends on a tiny pin-hole to empty their water when the rain stops. However, it is all too easy for this hole to become obstructed with small particles of sand or other debris common in a gutter. The ball then does not drain properly and the device does not reset itself. Thus, both devices required close monitoring and frequent manual cleaning in our system. I regret to say that I cannot recommend either one. My recommendation at this time is to employ a homemade Texas style standpipe roof washer. Its simplicity allows it to be constructed and maintained inexpensively.

We have now sold this house and moved to a different residence. We will work with the new owners who will continue using this system.

Rainwater Harvesting Discussion Forum:

http://groups.yahoo.com/group/rainwaterharvesting/

TO SEE THIS COMPLETE ARTICLE AND DIAGRAMS GO TO:
http://www.rwh.in/

[Jonesie]

Re: RAINWATER HARVESTING

I just found this person in Montrose, Michigan that sells water barrels and is willing to help anyone set up a system of barrels in which to collect rainwater:

rain barrels ANN ARBOR ISSUES TAX CREDIT see add - $18 (montrose)

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Reply to: sale-762854592@craigslist.org

Date: 2008-07-20, 6:18PM EDT

Great news the city of ANN ARBOR will give you a tax credit on your sewer usage if you install rain barrels. Check with the city for details. I sell barrels that can be made into rain barrels for $18. I have sold over 150 barrels so far this year. I assemble completed rain barrels with screened tops, spigot, and an over flow for $60 ea or 4 or more for $53 ea. You will harvest clean soft water for you plants and many other uses. Each barrel will hold 50-60 gal of water; FREE water. These barrels are recycled food grade heavy duty barrels with screw on lids. I will deliver 1-6 barrels to Ann Arbor for $45 or 7-12 barrels for $65 with my larger truck. I can deliver more using a 23 ft. trailer for $75.
If you want to make your own barrel I will show you how.



You can find the photos of his barrels here:

http://annarbor.craigslist.org/grd/762854592.html

I do not know him and I cannot vouch for it - but it sounds interesting...

"Regard it as just as desirable to build a chicken house as to build a cathedral.?
~ Frank Lloyd Wright ~