Rainwater Harvesting and Stormwater Reuse for Arid Environments - Design with the Desert: Conservation and Sustainable Development - page 371

Catchment
area

Conveyance/gutter

Roof washing
or first-flush

Discharge
pollution

Conveyance/gutter

Alternate
water supply

Storage

Overflow

Distribution/pipe

Non-potable
use

Purification

Distribution/pipe

Potable
use

FIGURE 21.5
Typical rainwater harvesting system components.

Several items are required to prepare a water budget: average annual rainfall data, a site
plan, and a water demand quantity. For a potable system, a residence's monthly water usage
table would be required. In some states a landscape water budget, a rainwater harvesting
plan, and an implementation plan are required to be submitted with development plans.
In October 2008, Tucson, Arizona, was the first in the nation to require commercial
properties to submit rainwater harvesting plans. Their City Ordinance, Chapter 6, Article
VIII Rainwater Collection and Distribution Requirements, outlines the requirements
for commercial properties to provide 50% of the site's estimated yearly landscape water
budget from rainwater harvested on-site. They allow a 3 year plant establishment period
before the 50% is enforced. This Tucson City Ordinance has set the stage for others to
follow* (Table 21.1).

21.5 Integrated Site Design
Integrated site design is intended to match site requirements (e.g., water, energy, food,
and aesthetics) with the eventual components of an area (e.g., stormwater runoff, shade
from buildings, and vegetation) while improving the function and sustainability of a site.
This process requires an integrated design process based on a multidisciplinary approach.
Every step of the design phase should be evaluated to pursue opportunities to achieve

* http://library.municode.com/html/11294/level3/PII_C6_AVIII.html (accessed August 19, 2011).