   Verde Values - September 22, 1999 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County The Verde Valley is a treasure that we often take for granted. Geologic formations, erosive forces of wind and water, climate, various life forms, and human activities have interacted over time to create the unique landscape we see today. One major factor that sets the Verde Valley apart from other similar Arizona landscapes is an abundance of perennial free flowing water. The Verde River, its tributaries, and the many springs in the area have created a lush and productive landscape. The Verde River watershed covers a 6,600 square mile area. All the precipitation that falls within the watershed will either infiltrate into the soil or, when the soil is saturated, flow either above or below ground to the river. I witnessed this phenomenon first-hand last week. I was traveling east on Interstate 40 near Seligman during a thundershower. I was waived into the left lane by road maintenance workers because the right lane of the freeway was a torrent 20 feet wide and 3 feet deep. As I drove south on Highway 89 through Paulden, I took the old Highway to take a look at Sullivan Lake. This is often considered the headwaters of the Verde River. A foot or so of silt-laden water was roaring over the dam, spraying mist, and forming muddy rainbows. Soil from Seligman, Ashfork, the Big Chino Valley, and other places was on the move. The rich, alluvial soils of the Verde Valley have been deposited on the flood plains over tens of thousands of years by these silt laden storm flows. At this point we can easily get sidetracked into some arguments about normal background vs accelerated erosion rates. This is a difficult issue to quantify and scientists are working to sort this out. Until the research is finished, it is important to realize that large expanses of the Verde River watershed uplands are covered with thick juniper stands. Juniper trees are rapidly encroaching on areas that may historically have been grasslands. When a juniper stand occupies a site, their root systems are very effective at acquiring soil moisture, more so than grass plants. The grass is slowly out-competed and juniper becomes the dominant plant and few, if any, understory plants remain to protect the soil surface. As a side note, many researchers think natural wildfires may have maintained a balance between juniper stands and grasslands prior to European settlement. Juniper control has been used successfully to promote grasslands, but it has a dollar cost. The negative effects of high flow storm events are greatly reduced by a healthy riparian ecosystem. Riparian ecosystems are the vegetation, habitats, and ecosystems found near lakes, rivers, streams or springs. Along rivers and streams of the Verde Valley, this is usually a narrow band of trees, shrubs, grasses, and sedges. This vegetation slows the flowing water and allowing silt to be deposited. When fur trappers entered the Verde Valley in the early 1800's, they described a series of marshes and beaver dams that created a wide, lush wetland. Today, we still have some very healthy riparian areas in the Verde Valley, but there is also much room for improvement. To improve riparian ecosystems, we must understand them. What follows is a short list of benefits associated with healthy riparian areas. Riparian vegetation dissipates the stream energy which reduces erosion and improves water quality. Large root masses develop which stabilize streambanks and reduce cutting of stream banks. The sediment is filtered and held on site which aids in floodplain development. These processes lead to improved flood-water retention and ground water recharge. The vegetation characteristics and water availability provide habitat and migration corridors for other organisms which leads to overall enrichment of the ecosystem. It's time to back up and look at the big picture. In the Verde Valley, we have excellent riparian resources. These resources are compatible with many human uses if we look carefully at the downstream effects of our actions. We can enjoy the benefits of recreation, livestock, fisheries, wildlife, minerals, visual quality, and more if we learn more about riparian ecosystems. We cannot, however, separate the upland watershed areas from those on the river and streams. They are closely connected. To learn more about the Verde River, come to Verde River Days on September 25 at Dead Horse Ranch State Park in Cottonwood. It starts at 9:00 AM and ends at C. If you have gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@kachina.net and be sure to include your address and phone number. |