Rain Water Harvesting and our Social Responsibility

Up to 70% our fresh domestic drinking water is consumed outside on the landscape.  By 9 a.m., after showering, using the bathroom, brushing our teeth and having a cup of coffee, each of us typically has used more than 30 gallons of water. After doing the dishes - 12 gallons per load - running the washing machine - 43 gallons per load - and watering the lawn - 10 gallons per minute - by the time we go to bed, we've used up to 150 gallons per person.

Nowhere is America's water crisis more evident than Lake Mead, just outside Las Vegas. The city has 2 million thirsty people - and gets 90 percent of its drinking water from the lake. 

Landscape designers have a social responsibility to reduce water use on the landscapes they design as well as educate clients on other options available to harvest water from other sources. 

Water harvesting will help save money on monthly water bills and reduce dependence on municipally-supplied water. A well-designed system will also decrease landscape maintenance needs.

Rain Water Harvesting Rooftop Collection Estimation:

  1 inch of rainfall on 1,500 sq.ft. roof could collect 900 gallons of water that can be used on trees, shrubs, and flowers.

Components of a Rainwater Harvesting System:

1. Catchment: the surface from which rainwater is captured.

2. Conveyance system: a means of moving the captured rainwater to where you want to store it. 

3. Means of Storage: locations where you can store the harvested rainwater.

4. Distribution System: rainwater stored in the ground or stored in tanks.

Water harvesting systems can be either active or passive, or a combination of both.

 A passive system directs harvested rainwater immediately into areas that are shaped to capture the water and allow it to percolate directly into the ground for use by plants.

A relatively shallow basin dug in the ground in order to collect rainwater, allows the water to sink into the soil. Basins are the most basic of all water collecting earthworks and will work in just about any situation.

Sculpting or contouring the landscape can capture all the rainwater that falls on a property in any given rain storm. Providing places for the water to be stored in the ground by creating berms, swales and basins, will yield quite a bit of water. Adding mulch on the top of the ground will increase the length of time the moisture remains in the soil.

 "If, as designers, we believe that design has the power to shape the future and that sustainability is something to strive for, how do we incorporate sustainability into our projects?" (APLD website)

COMBINING IRRIGATION WITH GARDEN ART

Olla - (ponounced Oy ya), can water plants in areas where water is hard to get, or plants that should not be watered frequently.

The Olla waters by seeping water through the unglazed pottery into the ground around the buried pottery.  It is an ancient practice by Native American gardeners as well as by the Spanish settlers.

Olla irrigation solves problems for gardeners who cannot irrigate frequently, and is a great solution for plants that should not be irrigated frequently. Ollas allow gardeners who travel and can not be at home to check on their plants and gardeners who are limited by water conservation ordinances to irrigate infrequently.

Ollas do not loose water to evaporation, but instead all the water sweats through the Olla into the ground. Ollas can also provide a great visual in your garden adding color and art to an otherwise drab area. Include some small boulders with the Olla, some flagstone, or even a small bird bath.

"No Dig" Garden Bed

Digging in our Arizona soils can be a difficult task, especially with the caliche we have. Instead of digging in the soil, try this sustainable and fun family project. Make your own "No Dig Garden Bed"! By doing this you will have a garden bed that's ready to plant in the spring, you will begin composting lots of debris from your yard and you will have done something sustainable in your yard. Here are the steps:


1. Decide where you want your garden bed. Remember you need at least six hours of sunshine, preferably the morning sun, on your garden. And remember the length of your garden beds should run East and West.

2. Lay newspaper or cardboard right on top of the grass. One layer of cardboard or five to ten sheets of newspaper will do the job. A good dimension for one bed is 4' wide by 8' long, but they can be any size that fits your needs. Overlap the edges by a few inches to ensure that you have all of the grass well covered.

2. If you want a boarder around your garden bed, then put it in place now. You can use lumber, plastic, synthetic wood, railroad ties, bricks, rocks, or a number of other items, get creative and sustainable and use something you already have.

3. Wet down the paper or cardboard layer. Give it plenty of water.

4. Start a layering of organic matter. Anything will work for this, leaves, grass clippings, finished or nearly-finished compost, and straw, ripped up newspapers, old vegatables from your pantry or refrigerator. You get the idea!

5. Add the organic matter, in three to four inch layers. At least four layers is best. Your finished height should be one foot tall. The organic matter will decompose over the winter, and the pile will shrink by more than half. Introducing earth worms to your organic matter will speed up the process.

6. Water the entire bed once you're done layering.

7. Spend the winter planning what you're going to put in your new bed.

By spring time, most of the organic matter will be broken down, and you can plant your garden.

Resource: planetgreen.com