We save everything else for a rainy day. Why shouldn’t we save the rain for a droughty day?
In the midst of this substantial summer drought, only those with irrigation and adequate water supply (as well as those lucky enough to receive a convective storm or two) seem to have green lawns, lush gardens, and healthy crops. Unfortunately, many folks can’t afford to water their lawns and gardens enough to stave off the baking heat. While irrigation is commonplace in agriculture, many farms only allocate parts of their land for priority watering. And even then, inefficient irrigation systems and improper watering timing can quickly deplete water sources. Water Conservation is extremely important!
What can we do?
Perhaps we should focus more attention on the storage of water in containers or promoting the storage of water in aquifers when we do receive rain. Lately, it seems like the weathery water hose is on full-blast or indefinitely kinked.
When it dries, it bakes and burns! Silent and deadly Sun has supplanted the patter of rain. In and out of cities, wind and flame advance relentlessly. Menacing fires have become commonplace these days. (Huffington Post Green Article.) Cities, often lacking much vegetation to burn, still scorch and bake in their asphalt and concrete ovens.
When it does rain, it pours. Occasionally, as the sky finally fades from blue, sharp, black tempests drop buckets of water on the land, perhaps doing more harm than good. The parched land can’t soak up rain quickly enough under heavy rain, producing stormwater runoff. In the country, flash flooding erodes loose soil in agricultural fields and deepens gullies. In the city, curb and gutter systems typically direct the relatively large amount of surface water that pours over roofs, roads and parking lots. Stormwater sewers sometimes become overburdened in heavy rains and cause problems. Retention ponds fill. Basements flood. Combined Sewer Overflows (CSO) occur where stormwater and wastewater systems have been combined.
The rain from an intense event, gravity driven, runs away rapidly or, as the sunlight returns, quickly re-evaporates into the atmosphere. Little is left that can benefit us and our surroundings for the longer-term.
But what if we made a strong effort to save stormwater for later use? How could we do this?
Here are a few ideas for rainwater harvesting, purification, storage, and use.
1. Rain Barrels
Rain barrels are usually small holding tanks attached to existing roof gutters. Rain barrel water isn’t usually purified, although many barrels utilize mesh openings to deter havens for mosquito larvae. Without filtration mechanisms, this sort of water is likely to be somewhat contaminated with atmospheric and roof pollutants. That said, the water is perfect for watering gardens and lawns nearby. Rain barrels typically have one or two openings for spigots to accommodate water levels and hose connections.
Cisterns are essentially large holding tanks for water. They can be operated similar to a rain barrel, or altered to improve water collection, filtration, purification, and use. Cisterns are already in use in areas with only seasonal heavy precipitation, places where municipal lines are impossible to tie to, or places where water is already heavily used. Earthships (as mentioned previously here and here) channel rainwater and snowmelt from the roofs into large cisterns buried in the soil berm encasing the home (“Water is precious, treat it as such“). Storing the cistern in a berm moderates water temperature and greatly lengthens the lifespan of the cistern itself. Eartships use various techniques to filter, purify, and prepare this stored water for
casual home use. (Video of Earthship cistern installation.)
3. Green Roofs
Green roofs are generally characterized as roofs covered by layers of vegetation, growing media, drainage materials, and waterpoof membranes. Green roofs reduce and delay stormwater runoff, filter air and water pollutants, add green space, reduce the Urban Heat Island Effect (UHIE), moderate interior temperature, increase the life of the roof membrane…the list goes on and on. Green roofs aren’t necessarily the best way to store water for human use in the long-term, but the ability of vegetation and engineered growing materials to filter out pollutants means that any runoff produced (and collected by rain barrels and cisterns) is already naturally filtered. Learn more about green roofs at GreenRoofs.org and GreenRoofs.com.
4. Rain Gardens
Rain Gardens are similar in purpose to green roofs, although they are generally situated at ground level. While green roofs usually use drought tolerant succulents, like Sedum, rain gardens tend to utilize native plants (See Missouri Grow Native!) that are tolerant of natural extremes in climate. Again, rain gardens focus more on the reduction and slowing of stormwater than capturing it for later use. I guess you could capture the outflow for storage, but the benefits of native gardening are already putting you ahead. Rain gardens can make up a portion of your landscaping that doesn’t normally require watering. This prevents the wasting of perfectly-good-for-human-consumption water on we-can-deal-with-natural-water,-thanks vegetation.
5. Living Retaining Walls
Living Retaining Walls (LRWs) are retaining wall systems that stabilize slopes with blocks that facilitate plants. I’ve posted about these several times. Similar to other living systems, LRWs reduce and delay stormwater runoff while covering what would normally be hardscape with vegetation. Any water draining from LRWs could possibly be stored for use, or fed into other green infrastructure like rain gardens (thus ‘saving’ the need to water more landscaping on dry days). Actually, it might even be feasible to store water in cisterns within the retaining wall, which could be used for drip irrigation. Oh, the possibilities!
All in all, we should focus on anything pervious that promotes local water storage or groundwater infiltration! Return Nature to the Urban Jungle.
Many, many people rely on groundwater for municipal, commercial and agricultural consumption. Paving over everything and pushing stormwater rapidly downstream is dangerous as a source of flash flooding and disrupts natural hydrology (streamflow, groundwater/surface water interactions, infiltration rates). Even where green space is present, construction and development have left it severely compacted, diminishing potential routes to aquifers. Thus, all of the ideas listed above, plus anything else that reduces/slows runoff, promotes groundwater storage, and provides reserves could be beneficial. Save it for a not-so-rainy day!