Water Conservation and Following Natures Blue Print

 

NOAA National Weather Service

Hillsborough County has designated this April as water conservation month. As everyone knows, we are in short supply of clean drinking water, so governments, national and local work to conserve this important natural resource.

 

So, what does conservation of water look like in areas like Hillsborough County, Florida? It entail things like low flush toilets; water restrictors in shower heads; restrictions on days and times yards can be watered; low water use washing machine; downspout water barrels; and reclaiming waste water.  On a more regional basis, governments have set aside land for water management and flood control. All of which have done a lot of good to help to conserve a very necessary resource. Yet the problem continues to get worse.
 
In light of the United Nations recent declaration to work with nature to solve our problems rather than going to war with nature we should consider looking for water conservation practices that work with nature. Read more about this declaration here:

https://planetearthneedsyou.blogspot.com/2021/03/the-united-nations-has-taken-bold-new.html 

 

So let’s look at how nature provides the planet with fresh water. Nature has evolved a very effective way of providing the planet with drinkable fresh water called the Water Cycle. Water from the oceans and lakes and rivers evaporates and rises into our atmosphere; also water taken up by trees and other plants returns to the air by transpiration. As water vapor, it rises high in the sky where it condenses into clouds. The various types of clouds will produce the different types of precipitation that return the water to the planet's surface. How that precipitation is distributed over the planet's surface is determined by climate zones and the local daily weather that occurs. Some places get too much water too fast, other places too little and the lucky places get just the right amount at just the right times. But even under the best conditions we often need to store water for, well, a sunny day.

Nature has evolved some good storage solutions. The obvious ones are lakes and rivers. But probably the one we never see is the best- the underground aquifer. Water stored naturally in underground aquifers has provided water for mankind in places where precipitation may only occur once a year or has not occurred on any regular basis for thousands of years. The historical oasis in the desert is the classic example. However, in today’s modern world, underground aquifers have become an integral part of man’s water supply.

 

There are pros and cons to both surface storage and underground aquifers that are worth noting. A good feature of surface water storage is that it is easy to access and that all the water in the structure can be drawn out. On the other hand, it is susceptible to pollution from runoff. Also surface storage will lose a large percentage of its volume to evaporation.

 

Underground aquifers have a unique advantage in that they have a filtering characteristic that collects pollutants near the top allowing deeper sections of the aquifer to hold cleaner water. On the con side of the equation, not all of the water in an aquifer can be extracted, some times less than half of what is held in the aquifer.

 

Fundamentally, to become an aquifer, water must make its way down through the surface and find any space in the bedrock below the soil. It could be cracks and caves in solid limestone or just the spaces between sedimentary rocks like sandstone, or any combination thereof. Two critical conditions must be satisfied for water to find its way to the open spaces in the rock below the surface soil. First, the surface must be both porous and permeable, that is to say it has to have a structure that can hold water and let it move down through it- similar to coffee grinds in a coffee maker. And second, the water landing on the surface has to remain there long enough to seep down through the soil.

 

Nature has evolved conditions that meet these criteria. The canopy of trees slows the fall of rain onto the surface as does the under brush in the forested area. The roots of the trees and brush break up the soil and create spaces for the water to both hold and percolate down. The worms and insects burrow into the soil making pathways where the water can seep down to the bedrock below. On the forest floor the accumulation of decomposing plant material provides a thick porous and permeable layer that readily holds the water from running over the surface too quickly. This allows the water to reach the voids below and form an aquifer before it flows down hill to a gully, or stream and finally to a lake or bay at the shore.

 

Let’s look at our underground aquifer, and what happens when we build a residential housing development in what was a natural forested area. The procedure most often followed is to completely remove all vegetation where roads, homes, playgrounds and retention ponds will be built. In some very few cases small natural areas are left intact within or adjoining the development.

The pictures below show  removal of all plant life from development sites in Florida.

During the construction phase the vast majority of the land is now barren soil. The roads and storm water system with its retention ponds are built first.

The pictures below are from actual Florida development sites.

With each rainfall, soil and silt wash into the roads and down the storm drains and empty into the newly created retention ponds. Here the soil, silt and dust settle out and line the bottom of the ponds with an impervious layer of sediment. The water does not percolate down to the aquifer but fills up until it overflows via the storm water piping system eventually entering one of the local rivers. From there it empties into a bay or an ocean. This is a significant loss of fresh water during this phase, and continues as homes are constructed unless the retention ponds are dredged regularly. The following are pictures of sediment washout at an actual Florida development site.

Eventually houses and local playgrounds are built and the barren soil is replaced by sidewalks, driveways, roof tops, patios and some number of backyard pools. None of these allow water to percolate down to the aquifer. The home site yards and the playgrounds are planted with turf grass, a few trees and shrubs, and sprinkler systems are installed to keep them well watered during the dry periods. Only a very small percentage of the new surface holds the water long enough to allow it to recharge the aquifer. So we are now in a situation where we are no longer saving water in the aquifer, but pumping more out to water landscapes, wash clothes, take showers, and flush toilets. The following are pictures of runoff from pavements and turf grass causing street flooding in a Florida residential development.

So what can we add to the current list of water conservation action that use nature’s ways of handling water storage to counter the effects of residential development? Here are a few actions that should be tried.

 

·      Clear lots for building as close to the scheduled construction time as feasible.

·      Any area that is not going to have a structure on it or become an athletic field should not be striped to bare ground. It should be left in its natural state.

·      When increasing the size of a home, build up and not out. I.E two story instead of single story.

·      Limit turf grass to athletic fields that require such surfaces.

·      Use locally friendly ground covers and plantings that require little to no water on home lots and common areas.

·      Dredge retention pond as needed to ensure the bottom remains permeable to allow recharge of the aquifer.

·      Build berms around retention pond to increase their capacity and have them first empty into natural areas before flowing into the storm water system.

 

Such measures by leaders in our communities should help conserve water, increase aquifer storage and help mitigate overloading of storm water systems and rivers that result in flooding. Turf grass does not hold rainwater long enough to percolate down to the aquafer below. Because it is maintained at a low height and the cuttings are not removed but left to settle on the surface they result in a very impermeable surface. Less turf grass also helps fight climate change by reducing the use of lawn maintenance equipment that sends greenhouse gases into the atmosphere and also means reduced use of herbicides, insecticides and fertilizers that pollute our drinking water. The following is a link to the Florida Friendly Landscape webpage that will guide you in making your little piece of the planet more in tune with nature’s way of conserving and replenishing clean water.

 

Florida-Friendly Landscaping™ Program - University of Florida, Institute of Food and Agricultural Sciences - UF/IFAS (ufl.edu)