|Shields Jr, Fletcher|
Submitted to: American Society of Civil Engineers Water Resources Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/2/2003
Publication Date: 3/1/2004
Citation: Shields Jr, F.D., Knight, S.S. 2004. Ten years after: retrospective evaluation of a stream habitat restoration project. American Society Of Civil Engineers Water Resources Conference Proceedings. p. 38-50.
Interpretive Summary: Stream channels in agricultural landscapes are often subject to accelerated erosion. Woody vegetation in riparian zones is often absent due to previous managment practices, but if such vegetation can be re-established, erosion control, water quality and habitat resources benefit greatly. Willow species are often used for revegetation projects because they root from cuttings and grow rapidly. However, survival and vigor are often disappointing in the harsh conditions typical of many channel banks. Previous experiments in a greenhouse showed that soaking willow cuttings for about 10 days before planting was extremely beneficial. This study was intended to verify the greenhouse results under field conditions. About 4,000 willow cuttings 1 to 2 inches in diameter and 6 to 7 feet long were planted at various elevations in in various types of soil along Little Topashaw Creek, Mississippi. Cuttings planted in selected plots were monitored closely for the first year following planting. Results from the first growing season clearly indicated an increase in early survival of soaked willow posts compared to unsoaked cuttings. These findings will allow landowners and others interested in establishing woody vegetation along streams to do so in a more cost-effective fashion.
Technical Abstract: Long-term assessments of ecosystem rehabilitation project effects are rare. Herein we describe a study of the Hotophia Creek rehabilitation project in northwest Mississippi. Fish and physical aquatic habitat data were collected for one year prior to construction of a one-km long stream habitat rehabilitation project in 1992. Habitat rehabilitation consisted of extending existing stone spurs, placing stone toe, and planting willow cuttings. Post-construction monitoring was conducted for the four years following construction, and at 10 years following construction. Parallel monitoring was conducted on an untreated reference stream and on untreated reaches upstream on Hotophia Creek. Effects of rehabilitation on habitat and fish communities were found to be positive in both the short and long term. For example, after 10 years, mean water depth in the reach subjected to rehabilitation was more than twice as great as for untreated reaches upstream. Woody riparian vegetation more than doubled and large woody debris density increased by an order of magnitude in both treated and untreated streams. Fish populations shifted away from domination by large numbers of small, opportunistic generalists and toward dominance by large-bodied, pool-dwelling species typical of more pristine streams. Prior to rehabilitation, 51% of the fish captured were cyprinids (minnows), while 10 years later 61% of the fish captured were centrarchids (sunfishes).