Gardens, Rain Gardens and Xeriscaping

The average rainfall in Helena, Montana is about 9-12 inches a year and landscaping accounts for half of all residential water consumption.  Adopting sustainable practices in outdoor landscaping allots for one of the largest opportunities for water savings.  This page includes information on Xeriscaping, Rain Gardens, and Rainwater Harvesting.  If you have any questions please contact the Lewis & Clark Conservation District. 

Xeriscaping

senecio

The term xeriscaping stems from the Greek word xeros meaning “dry.”  This technique is important to us here in Helena, Montana due to our high elevation semi-arid climate (basically a mountain desert).  Xeriscaping is important because this term represents a water conscious, water efficient landscaping method.  

Economically, Xeriscaping reduces water and maintenance costs, enhances real estate values, increases plant survival, and allows for edible and/or decorative products.  

Environmentally, Xeriscaping improves water and soil conservation, reduces use of petroleum products, improves air quality, enhances urban wildlife habitat, and reduces water contamination.  

sheep fescue

The NRCS, DNRC, and the Montana Association of Conservation Districts have compiled an excellent file on Creating Native Landscapes in the Northern Great Plains and Rocky Mountains which, will go into further detail, planning steps, what to avoid, and plant options.  If you have any further questions please contact the Lewis & Clark Conservation District.

Rain Gardens

A rain garden is a plot of land that has been lowered, a hole or depression, and planted to capture water from impervious runoff such as roofs, sidewalks, and other urban structures that do not allow rain water to penetrate into the ground.

Rain gardens are important because as cities grow there is an increase of impervious surfaces which can lead to flooding which, is dangerous not only because it can destroy homes and property, but also because it carries pollutants from parking lots, streets, and lawns into your streams and lakes. An increase of impervious surfaces also threatens our groundwater by not allowing a relatively even displacement of groundwater recharge, which can directly lead to the reduction of the quality of our water.

 

Creating a rain garden is simple, it is similar to a perennial garden with a few exceptions.  Besides being placed strategically to collect rainwater runoff from your home or sidewalk, or other impervious surface, they need to be placed somewhere with good soils where adequate drainage rates exist.  You will also want to keep your rain garden away from septic systems, water wells, utilities, and foundations.  Your rain garden should also be around 5-10 percent of the size of the impervious area that will be distributing runoff into the garden.

For example:

(3,000-square-foot roof) x (7% = 0.07) = 210 square ft

So your garden should be 21 feet long by 10 feet wide!

Rainwater Harvesting

How to build your own system.

Rain water collection can be used to supplement your main supply of water.  Harvesting rainwater can help reduce the severity of flooding, can provide water if there is a drought, and can reduce the demand on your well.  Rainwater harvesting can also help in the availability of potable water because there aren’t problems with salinity and other salts.  Harvesting rainwater provides a benefit to the water supply and wastewater subsystems.  Harvesting helps reduce the capacity that flows into stormwater sewer systems and stormwater runoff which usually carries pollutants into freshwater bodies.

Collecting rainwater is a fairly easy task and there are many different methods that can be established within a rainwater harvesting system.   You can create your own system by hand or you can buy systems, you can store them outside, underground, or you can build an enclosed system where your drains directly lead to. You can use harvested rainwater to water you plants and potentially drink.  There has been a lot of work focused on the development of Life Cycle Assessment and Life Cycle Costing methodologies to assess the level of environmental impacts and money that can be saved by implementing rainwater harvesting systems.