Case Studies

Portland Pollution Control Lab


This case study illustrates a number of techniques of collecting and storing rainwater. The Pollution Control Lab facility in Portland, Oregon was designed by architect Miller-Hull and landscape architect Robert Murase.  This image shows rain water scuppers draining water from the roof. The water is being harvested and could be used to fill a pond or cistern for later use.

Metal is the best choice for roofing when water is to be harvested use since it will be less contaminated by the chemical composition of the roof.

Scuppers drain water into a bioswale

In this image water is delivered by the scuppers to the swale.  The storm water collection, treatment and storage is visible as a design function of the site. 

Water tolerant plants remove excess nutrients and the roots and soil capture and immobilize particulates in storm water run off.  The swale should be lined with compacted clay or a synthetic liner if the soil permits the water to infiltrate rapidly.

Parking lot bioswales

In this image a bioswale receives water from adjacent parking bays.  Notice that there are no curbs but there are wheel stops to keep the cars from damaging the plants.  The swale is a depressed area that slopes gently to one end.  Good water quality improvements occur with as little as 200 linear feet of swale.


Retention Pond

The winter and summer views of this retention pond change dramatically.  The large planting of ornamental grasses and flowering shrubs make this garden beautiful in spring, summer and fall.  In winter the grasses are cut and the pool becomes the primary focal point.  The viewing dock and the design of the pool edge display the changes in water level during the seasons.  In this way the storm water run off is interpreted by the design for the user.

Up stream of the pond is residential development that generates non-point pollution from lawn fertilizer, pesticides animal wastes, sediment and pollution from automobiles  (PCB, hydrocarbons and atomized rubber).  The amount of sediment was greater than anticipated so an sedimentation basin was added to the upstream side of the pond.

Temperature and Precipitation in Moscow

The ability to harvest water depends, of course, partly on how much precipitation there is.  This table shows a twenty-two year average of precipitation in Moscow. 



Santa Ursula


In this small Mexican community, a "lavanderia" (community laundry) was built with water harvesting principles. This project was designed by Accion y Desarrolo Ecologica, Daniel Wintterbottom, and students of University of Washington in Santa Ursula (Winterbottom, 2000). The project consisted of butterfly shaped galvanized steel roof tops collecting water and emptying it into 20x10 foot ferrocement cisterns (Winterbottom, 2000). (pictures) From the cisterns, the water is pumped into smaller open cistern in which the people do laundry. The dirty water is then directed into a grease separator and filtration system then run into an adjacent orchard for irrigation purposes (Winterbottom, 2000). These cisterns will provide up to one half of the needed water during the dry season. There are plans to enlarge the system so that there will be enough water to supply all throughout the dry season. "This project serves as a demonstration model... relieving the natural systems of contamination and providing sustainable amenities to the community" (Winterbottom, 2000).


Residential Design Demonstration

Amazing reductions in water use are possible through conservation. Ms. Lizett Fife compiled data on the collection and grey water reuse  experiments her home in Moscow. She demonstrated a 50% reduction in the annual use of water by the residence.  This resulted in an annual reduction in potable water use of more than 63,000 gallons.

Water collected from the roof of the existing house and garage resulted in about 17,000 gallons annually.  This water could be dedicated to irrigation of the the landscape.  On site treatment of grey water and then using it to irrigate the landscape is also a viable process.


Main Floor Plan

Discuss 12 elements in Ms. Fife's proposed house and site that would result in a more sustainable residence.

This is a proposed house design for a small lot.

The proposed design of this residence for greatest sustainability is based on the 12 measures.  Those related to water conservation are listed below.

1. Install a composting or low flush composting toilet system

2.  Collect and reuse grey water for irrigation

3.  Collect and store rainwater

4.  Landscape with drought tolerant plants

5.  Specify energy and water efficient appliances for the home

6.  Compost landscape and kitchen and waste and reuse a mulch.

House Plan

House Section

Draw a section of the residence designed by Lizette Fife.  Discuss the design concepts for the building and the site that define this as a sustainable building and site.

The cross section illustrates the extent of the roof overhang to shade the windows in the summer and to allow full penetration of sunlight into the rooms in the winter.  The rainwater collection cistern, shown on the right, is designed as a visible and attractive architectural element rather than being buried.

When rainwater is collected from a roof it must be stored for later use.  To calculate the amount of water that can be collected (and to size the cistern) follow the method indicated below.

0.62 gal per inch x roof Sq. Ft. x inches of rain per year x .9 efficiency = total gallons

For example if the annual rain fall is 10" and the  roof is 1000 square feet then

0.62 x 1000 x 10 x .9 = 5,580 gallons