Rainwater Harvesting Student Z

SCI-218 Natural Resources

Southern New Hampshire University

Rainwater Harvesting: What is it?

Rainwater harvesting is a catch system that stores rainwater in rain barrels or

tanks (above or below ground). The stored water can be used for many

purposes, both potable and non-potable:

Potable (With Filtration System) Non-Potable

Drinking/Tap Watering a Garden and Other

Outdoor Plants

Cooking Toilet water

Washing Dishes Large-Scale Irrigation

Bath and Shower

Washing Cars

Rainwater Harvesting: How it Works

Rainwater harvesting typically collects rainwater from roofs via a downspout

diverter that connects to a storage system (See Figure 1). In addition to the

diverter, there is also a filter screen which prevents large debris from getting

into the system.

The storage system (See Figure 2)

A hose runs from the diverter to storage.

An overflow hose is also attached to the storage system to divert excess water

away from housing foundations.

A spigot or ball valve are installed at the bottom of the storage systems for

dispensing water.

Storage systems can be easily expanded upon by adding connecting another barrel

or tank.

Figure 1 shows a downspout diverter

which also has a filtration screen inside

the unit.

Rainwater Harvesting: How it Works Diverter connected to downspout Plastic tubing running from the diverter

Plastic tubing connected to rain barrel with

overflow PVC vent that connects to overflow tube

Rain barrel with spigot and plastic overflow tube

pointing away from the house

Figure 2 shows a basic

rainwater harvesting

system.

Rainwater Harvesting: History

Rainwater harvesting has been used by many civilizations, dating as far back

as 10 BC (Leung, 2008).

Romans where known to have used rainwater harvesting for watering crops,

consumption, and creating cooler microclimates (Leung, 2008).

Large underground cisterns (see figure 3) were used to prevent the water from

becoming polluted (Hasse, 1987).

It is suspected that rainwater harvesting began to fade out due to the

advancement of routing streams to urbanized areas (Hasse, 1987)

Figure 3 shows an

ancient

underground

Nabataean cistern

used to store

rainwater.

Fahlbusch, 2008.

Rainwater Harvesting: Modern Day

Applications and Benefits

USES BENEFITS

• Irrigation

• Drinking/Cooking

• Bathing

• Toilet Water

• Dishwasher

• Outdoor watering

All uses help to:

• Decrease the demand on fresh water

supplies.

• Manage stormwater runoff, pollution,

and erosion caused by it.

• Provide people with a viable solution

to water shortages in areas drought

susceptible areas.

• Decrease annual costs of from public

water use.

Rainwater Harvesting: Disadvantages

Disadvantages of rainwater harvesting:

Cannot be used as a primary source of water since it is dependent on rainfall

Storage limitations

Can become polluted from animal droppings or other roofing leachate

Requires regular maintenance – especially on large scale applications

Cost can be somewhat high at first: $200-$23,000 (EFA, 2015), depending on the size, material used, and type of filtration system.

Rainwater Harvesting: Global

Significance

Global uses for Rainwater Harvesting:

Backup water storage during drought or

natural disaster

Is a viable source of water in arid areas of

the world

Helps to meet global demand for water

Reduces global pollution and land erosion

from runoff

Preserves habitats effected by flooding,

erosion, and pollution

Rainwater Harvesting in Uganda. United Nations

University, 2012.

Rainwater Harvesting in Australia Used for drinking water, outdoor watering, fire water, and waste

water (i.e. toilet and bath)

Used for commercial applications (see figure 4)

Is a viable source of water in a country where water is naturally

scarce

In Australia, 22% of the population owns a rainwater harvesting

system (NSW, 2015).

This helps to significantly reduce public demands on an

already limited fresh water supply.

Figure 4 shows 2 out of 5

rainwater collection

tanks in Australia. Each

tank holds 4 megalitres

of water which is used

for fire and drinking

water. Rhino Water

Tanks, 2015.

Rainwater Harvesting in South Korea Rainwater Harvesting is primarily used as a backup water source during times

of drought and natural disasters (SEI, 2009).

During Monsoon seasons, a years worth of water can be delivered within 3

months (WaterWorld, 2015).

South Korea has offered developers incentives to help alleviate any financial

burdens associated with implementing a rainwater harvesting system.

Builders are allowed an extra 3% of floor space beyond regulations if rainwater

harvesting systems are implemented (Han, 2009).

Pictured is Professor Han, a

major global advocate of

rainwater harvesting.

Professor Han has brought

rainwater harvesting to the

forefront in South Korea

through research and bringing

public awareness

(WaterWorld, 2015).

Rainwater Harvesting: Materials

Materials Use/Function

Rain barrel(s) or tank(s) Stores rainwater

Downspout Diverter (see figure 5) Connects to gutter downspout and

diverts water to storage

Hose or Piping Connects diverter to storage and

redirects overflow away from house

foundations

Spigot Dispenses the rainwater

Screen or filter Prevents large debris from entering

storage

Pipe/Hose Straps Secures pipe/hose to house

Hacksaw For cutting downspout

Screw driver/Drill For securing diverter and hanging

pipe straps

Zip Ties For securing the tube to downspout

Box Wrench For tightening the nut on the inlet

attachment

Figure 5 shows a modified stock

photo of the Fiskars diverter from

Amazon.com.

Rainwater Harvesting: Action Plan Phase I

Connecting the downspout diverter to gutter

system:

Measure the length of the diverter and then subtract 4 inches.

Take this measurement and mark it on the downspout gutter where you

plan to attach the diverter.

It is recommended to detach the downspout gutter to make the next

step a little easier.

Using the measurements from before, cut into the downspout using a

hacksaw. Be sure to use caution after making the cuts. Most gutters

are made out of aluminum and will have a sharp jagged edge after it’s

cut.

Once the downspout is cut, fit the diverter to each end. Reinstall the

downspout if necessary. Make sure the diverter is where you want it

and then secure the diverter with screws.

Rainwater Harvesting: Action Plan Phase I

Preparing the rain barrel or tank:

Using a spade drill bit, cut a hole in the top lid

The hole’s diameter should be slightly less than the inlet attachment’s diameter

Note: Inlet hole can be cut on the side of the barrel but must be as high as possible.

Insert the inlet through the top of the rain barrel and tighten the nut using a box wrench

Repeat the same steps when installing an overflow tube, except the outlet hole should be located on the side of the barrel and slightly below the level of the inlet hole.

Drill a hole on the side, towards the bottom of the barrel for the spigot. Be sure to use a spade bit which is slightly smaller than the diameter of the spigot.

Rainwater Harvesting: Action Plan Phase I

Attaching the hose from the diverter to

the rain barrel:

Measure the distance from the diverter

to where you plan to put the rain barrel

Use this measurement to pick out the

right hose length

Run the hose down the downspout and

secure using zip ties

Connect the hose to the rain barrel

inlet

Use duct tape to wrap around the

inlet if the hose is loose

A hose clamp can also be used to

make an even tighter connection

Additional notes and materials:

The overflow hose should be pointed away from

the house’s foundation.

Landscaping rocks can be used around the rain

barrel and overflow hose to prevent erosion.

The rain barrel should be below the Diverter and

raised up off the ground to allow fill clearance.

The rain barrel should have a cover to prevent

contaminants and insects from getting into it.

A ball valve can also be used in place of the spigot

in order to allow the attachment of a garden

hose. Note: Rain barrel should be higher than the

watering areas for achieving enough pressure.

Rainwater Harvesting: Action Plan Phase I

Rainwater Harvesting: Action Plan Phase II

Increase the amount of storage capacity

Install rain barrels at a higher point in order to increase water

pressure for outdoor uses

Connect an electric pump to the rainwater harvesting system which

will be solar powered

Add Pex plumbing for interior use

Plumbing will run from the water source, to the pump, and then to two

toilets

Ball valves will be installed with each toilet for switching from rainwater

to municipal water

Rainwater Harvesting: Conclusion and Goals

The purpose of implementing a rainwater harvesting

system:

Decrease the amount of runoff and pollution that comes from our

property

Cutback on our municipal water use for both indoor and outdoor

uses

Significantly decrease the amount of wastewater that comes from

our toilets and dishwasher

Lessen the strain placed on fresh water supplies

Become more self-sufficient and rely less on public systems

Spread knowledge and awareness to friends, family, and neighbors

who inquire about the system

References:

Energy and Environmental Affairs. (2015). Demonstration 5: Rainwater Harvesting. Retrieved May 22, 2015, from http://www.mass.gov/eea/agencies/dcr/water-res-protection/ipswich-river-watershed/demonstration-5-rainwater-harvesting.html

Fahlbusch, H. (2008). Water in Antiquity, an introduction. Retrieved June 16, 2015, from http://www.romanaqueducts.info/webteksten/waterinantiquity.htm

Han, M. (2009). Rainwater Harvest System – Star City, Seoul. Retrieved June 12, 2015, from http://www.fbr.de/fileadmin/user_upload/files/Englische_Seite/Han_WS_1_2009_engl_webseite.pdf

Hasse, R. (1987). Rainwater Reservoirs above Ground Structures for Roof Catchment. Retrieved June 12, 2015, from http://wgbis.ces.iisc.ernet.in/energy/water/paper/drinkingwater/rainwater/introduction.html

Leung, J. (2008). Rainwater Harvesting 101. Retrieved May 23, 2015, from http://www.grownyc.org/files/osg/RWH.how.to.pdf

NSW. (2015). Semi-arid woodlands (shrubby sub-formation). Retrieved June 12, 2015, from http://www.environment.nsw.gov.au/threatenedSpeciesApp/VegFormation.aspx?formationName=Semi-arid woodlands

Rhino Water Tanks. (2015). Commercial Water Tanks - Corrugated. Retrieved June 16, 2015, from http://www.rhinotanks.com.au/index.php/commercial-water-tanks/commercial-water-tanks-corrugated/

United Nations University. (2012). Rainwater and Health in Developing Countries: A Case Study on Uganda - United Nations University. Retrieved June 16, 2015, from http://unu.edu/publications/articles/rainwater-and-health-in-developing-countries-a-case-study-on-uganda.html

WaterWorld. (2015). South Korea. Retrieved June 17, 2015, from http://www.waterworld.com/articles/wwi/print/volume-27/issue-4/editorial-focus/stormwater-management/south-korea.html