Eight Water-Harvesting Principles

The Eight Rainwater-Harvesting Principles appear in greater detail of both volumes of Rainwater Harvesting for Drylands and Beyond, but can be downloaded here to get you started.

Calculating Rainfall Volumes

Calculating Rainfall Volumes, from Volume 1, provides instructions and examples of how to determine how much rain, in English or metric units, falls on a catchment area in a given rainfall or an average year.

Calculating Runoff Volumes

You can get a ballpark estimate of runoff volume from any sloped surface by multiplying the volume of rain
that falls on that surface by its “runoff coefficient”—the average percentage of rainwater that runs off that type
of surface. For example, a rooftop with a runoff coefficient of 0.95 estimates that 95% of the rain falling on that
roof will run off. The runoff coefficient for any given surface depends on what the surface is composed of. Rainfall intensity, soil type, and vegetation density also affect the coefficient. Calculating Runoff Volumes, also from Volume 1, lists the runoff coefficients for several types of catchment surfaces and gives examples of how to use this number when calculating runoff volumes in metric or English units.

Permaculture Ethics and Design Principles

This version of the Permaculture Ethics and Design Principles was compiled by the Permaculture Drylands Institute and the Sonoran Permaculture Guild.

Designer’s Site Assessment Checklist

A four-page annotated checklist, the Designer’s Site Assessment Checklist guides you through the basics of a site assessment, from General Information, Site Observation, Site Information, to the Human Factor, describing each section and its components in relatively detailed paragraphs.

Using Google Earth for Site Assessment & Reporting

Generating Site Maps and Reports with Google Earth (downloadable PDF)
These step-by-step instructions offer one method of performing an initial digital site assessment using Google Earth, Google Maps, and other common applications. Updated June 2010.

Sample Basic Site Report (downloadable PDF)
Additional Site Map 1 (downloadable zipped JPG)
Additional Site Map 2 (downloadable zipped JPG)
These 3 documents were created using the instructions above. The documents are fairly simple, and are intended only as a representation of the techniques described, not as a complete site report.

For more handouts, click:
Greywater Handouts
Watergy & Climate