The temperature is topping 90 degrees again today in Eastern Arkansas. The Delta is finally drying out from extensive flooding of the Cache and lower White Rivers, which both reached levels unseen since the 1970's this spring. Our site held up beautifully despite the high water; we plan on re-surveying monumented cross-sections and longitudinal stream profiles this fall to measure rates of erosion or deposition within the new channel and floodplain.
It seems that, by mere chance, most stream restoration efforts get tested by some extreme weather event immediately following or during construction. Delta Project Manager Matt Lindsey (pictured below within our constructed "E6" stream type channel) remembers a project he worked on in the Gulf Coastal Plain of Mississippi during the summer of 2005. "When Katrina hit we got over 5 inches of rain on our site in a matter of a few hours and category 3 hurricane force winds. Needless to say, being in the middle of construction, this set us back a few weeks. After that, a 30-year flood event seems mild."
Many thanks from the Arkansas Nature Conservancy staff to the many volunteers that came out last Friday to help install willow and sycamore live stakes at our stream restoration site. A diverse assemblage of over thirty individuals braved the cold, wet weather and successfully planted three thousand native trees along Benson Creek's new, meandering streamcourse. The group included sixteen students from Brinkley High School and several members of the organization of Central Arkansas Master Naturalists. Again, for your enthusiasm and hard work... thanks.
As of December 2007, Benson Slash Creek is again a free-flowing stream. Over the past few weeks we have hydrologically connected Benson's newly-restored streambed and created a series of floodplain wetlands out of the century-old agricultural channel that previously confined its flow. Hydrostatic pressure transducers set within the stream and down in wells among the floodplain monitor the changes in site hydrology in response to restoration.
Recent video from Yahoo's Assignment Earth (click on link to view) highlights our ongoing effort to transform Benson Slash Creek from an agricultural ditch into a natural stream.
It has been six weeks since thousands of live buttonbush and willow cuttings were installed throughout the restoration site, and the results are dramatic. At this point we are seeing around 95% survival rates, meaning that only 1 out of every 20 live stakes has failed to sprout new leaves and branches.
"We will probably observe slightly higher mortality rates when the weather turns drier and hotter as July and August set in," says Restoration Technician Clint Harris, who is overseeing much of this project's bioengineering. "If the plants looks as healthy undergroung as they do above, however, their root systems should be able to support them through the summer months."
Pictured at left, a mass of cricket frog eggs has been attached to a newly-sprouted buttonbush sapling. This is only a small example of the many native species that have begun to re-colonize Benson Creek during the process of construction. Tracking these biological changes is an important aspect of this restoration project.
Last week construction began on Phase three of the Benson Creek Stream Restoration project. "This phase involves digging and stabilizing what is referred to is an E channel," says Delta Project Manager Matt Lindsey. An E channel is best described as a highly sinuous stream type with a low width to depth ratio (meaning that it is relatively narrow and deep).
In this case we are digging a channel that is around 3 feet wide and 2 feet deep. E channels are characterized by their natural box-like shape and often overhanging banks. Relying upon thick, deep root systems of riparian vegetation and a highly developed floodplain, the streambed and banks of E channels are highly stable, meaning less sediment entering downstream.
Here, Cache River Project Manager Josh Duzan and volunteer Holly Clinkingbeard (of Fayetteville, AR) install biodegradeable jute fiber matting over a bed of hay and native seeds. This will temporarily stabilize the stream while wetland vegetation takes hold.
Sore backs, knees, arms, and hands attest to the three-thousand live stakes installed at our stream restoration site over the last two days. Many thanks to Arkansas Nature Conservancy staff Mike, Clint, Kyle, Seth, Joy, Roger, Sagar, Julie, and Jerry...and thanks especially to our volunteer Robert. This is a not-so-glamarous task but the results should be outstanding. Stay posted for survival and growth rates in respose to your hard work.
Springtime has officially hit the Arkansas Delta as teperatures rise to the 60's and 70's during the day, encouraging new plant growth on our restoration site. Hundreds of live willow stakes that have remained dormant since installation are now vigorously producing leaves and root-systems essential to the stability of the carefully-sculpted streambanks.
Over the next two to three weeks, we plan on installing an additional three- thousand black willow and buttonbush live stakes within the newly constructed stream. We are trying to take full advantage of the present mild temperatures and moist soils that are optimal for plant growth and propagation.