Page 40 - Green Builder March-April 2016 Issue

Good Design.
A mulch layer can
capture some of
the sediment
flowing into a
bioretention cell.

CREDIT: CLEMSON UNIVERSITY

Trap it. A “sediment trap” is a small depression bordered by a CREDIT: ENVIROMAT
small berm that captures and collects sediment at the entrance to a
bioretention area, such as a rain garden. Use traps at the inflow of Tough Customers. Plants chosen for green roofs in arid and
green infrastructure features to facilitate the removal of accumulated semi-arid regions should be able to tolerate wind and temperature
sediment and prevent the feature from becoming clogged. extremes, as well as periodic drought.

Maintain it. If you include a mulch layer or sediment trap in your Mulch it. Organic mulch can increase water retention and pollutant
stormwater management practice, regularly remove the accumulated removal while building soil structure and suppressing weeds. Note,
sediment to maintain its function. however, that many desert trees and shrubs react poorly when their
trunks come in contact with mulch.
5. LIMITED IRRIGATION SUPPLY
Maintain it. All landscapes require maintenance; xeriscaping is no
Limited water resources can be a barrier to green infrastructure in exception.
arid and semiarid regions. Follow the principles of xeriscaping to
conserve water, and create a plan that balances water supply and 6. SPACE CONSTRAINTS
demand. You will first need to determine the annual water budget
(assuming the feature will use native plants at native densities). Many green infrastructure features require land area to allow
stormwater to infiltrate into the soil. This can pose a challenge
Use low-water use plants. You can drastically reduce, if not eliminate
the irrigation requirements of green infrastructure by using native and
drought-tolerant plants. These include drought-tolerant shrubs and trees.
Rain garden plants should be able to tolerate occasional inundation.

Use efficient irrigation. Make your irrigation systems most efficient
by grouping plants according to their water needs, and by adjusting
the frequency and depth of irrigation according to plant type, plant
maturity and season.

Amend it. Healthy soils are essential to retaining soil moisture,
sustaining vegetation, and treating stormwater runoff. If your site’s
soils are poor, amend them with organic material.

38 GREEN BUILDER March/April 2016 www.greenbuildermedia.com