Friday, January 13, 2012
Here we are at the very beginning of a New Year and we all have great expectations for something much better than the past year.
I will take this opportunity to remind us of the most important natural resource we have in the Walla Walla Valley: clean, fresh water.
Fresh water is only 3 percent of the world's water supply. Only about 1.1 percent is potable. We all are greatly dependent on it for our sustainable long-term survival in this Valley. Every person, animal and plant shares a demand for clean water.
All of us have a responsibility to safeguard and conserve water on a daily basis if we want to retain our current wonderful lifestyle and productivity.
We live in an arid region with a vast range in annual precipitation due to elevation differences. At Wallula Gap, the country sits at 340 feet elevation and receives about 4 inches of precipitation a year, while up in the Blue Mountains at 4,869 feet the average annual precipitation exceeds 50 inches.
The Walla Walla Valley is unique because of the geological formations upon which we sit as well as its location along the western face of the Blue Mountains.
This amazing basin has provided us with many seeps, springs, streams and rivers that drain into this Valley and flow west into the Columbia River.
The native word Walla Walla is interpreted to mean "place of many waters." These waters come to us throughout the entire year, sometimes in floods and at other times in trickles.
It is this natural runoff of cool, fresh water out of the Blue Mountains that we need to think about here at the leading edge of this New Year.
I will start out by writing about flood plains, or those areas where the actual flow of water occurs on a daily basis and where a channel has been formed over long periods of time by the movement of water down-slope.
Flood plains, where streams and rivers are located, provide life and recharge our aquifers. These are where the water travels and moves about within its established buffer zones. These are areas where the water knocks around from side to side picking up and delivering cobble, wood and silts.
This is the area where riparian zones are established. The riparian zone is the buffer zone that protects shorelines from flooding, stops incised erosion of banks and delineates the edge of the flood plain.
The riparian zone also filters water, provides shade to keep the water cool and provides 82 percent of all Washington wildlife species a place to live during some part of their life cycle. Riparian zones are nature's way of announcing where floods will occur.
Riparian zones are made up of large native trees like black cottonwood, white alder, water birch, blue elderberry, many species of willows and other woody shrubs.
Healthy flood plains have numerous old channels that are braided, leaving and rejoining the currently inhabited channel. These hydro-geologic formations are always in flux as the water in them is always eroding away internal cobble bars or shorelines and creating point bars as the stream meanders.
Meanders within a channel are the stream's natural way of controlling its velocity and handling the volume of water from season to season. Another very important component is the introduction of large trees into the stream channel or flood plain.
These large trees provide scour pools that allow small fish and invertebrates to survive in cover in deep, cold water. Big wood, as it is called, is vital to the health of rivers and streams.
So this year as you look at Mill Creek, the Touchet River or the Walla Walla River up high in their systems you will notice a huge difference between these rivers east and west of Walla Walla and College Place.
Think about what caused these vast changes in the lower reaches of these rivers and what smart, conservation-minded landowners along these lower river reaches are doing to correct the issues and return these rivers to health.
Cold, clear water is worth more than any other resource, so this year please do your best to use this gift only when you need it.
For more information on how flood plains and the streams and rivers that live and function within them work, please call the WWCCD at 509-522-6340.
We will come visit your group, club or organization and speak to you on how to be a responsible steward of water and what the WWCCD is doing towards meeting that goal this year.
Mike Denny is the riparian habitat coordinator for the Walla Walla County Conservation District.