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https://hdl.handle.net/11681/4738
Title: | Recent and planned marsh establishment work throughout the contiguous United States : a survey and basic guidelines |
Authors: | Environmental Concern, Inc. (Saint Michaels, Md.) Dredged Material Research Program (U.S.) Garbisch, Edgar W., 1932-2012 |
Keywords: | Marshes Wetlands Wetland establishment Marsh establishment Projects Coastal wetlands Coastal marshes |
Publisher: | Environmental Effects Laboratory (U.S.) Engineer Research and Development Center (U.S.) |
Description: | Contract Report Abstract: Information on deliberate marsh establishment work that is planned, underway or completed throughout the contiguous United States within the period of 1970-1976 has been identified through (1) literature review, (2) interviewing people who, during the period of May 1975 through January 1977, have become known to be potential sources of pertinent information, and, (3) the completion of distributed information request forms by various correspondents. Excluding U.S. Army Engineer Waterways Experiment Station (WES) projects currently underway, marsh establishment projects at 105 district locations have been completed for at least 1 year and 14 projects are planned for the immediate future. Out of the 105 completed or continuing marsh establishment projects, nine were totally unsuccessful (due to vandalism, Canada geese eat-out, wave exposure too severe for seeding, or site surface elevations too low for seeding). Variation encountered in projects included 18 that existed in freshwater or nearly freshwater locations, 68 that existed on the east coast, 17 on the gulf coast, 8 on the west coast, and 12 inland. Fifty-nine were purely experimental, as opposed to applied or partly so. From information received and collated, practical guidelines for site preparation, marsh establishment, and site management and maintenance were developed and are discussed herein. The two most important factors found for preparing a site for marsh establishment. were surface slopes and surface elevations. Within the tidal zone, surface slopes should be developed such that they exhibit reasonable stabilities in the absence of vegetative cover. Surface elevations must be carefully considered in the design and planning of a project and tied in with the various zones of marsh types existing in the region. Surface elevations are most important and their acceptable tolerances most stringent in areas subject to tidal amplitudes of 2 ft or less. Long-term consolidation of fine sediment types is not considered of practical importance in achieving final surface elevations within acceptable tolerances. Close coordination between the site preparation and the marsh establishment stages of a project in terms of time of year is considered important; however, the use of nursery plant stock may alleviate the consequence of unacceptable marsh establishment because of unavoidable delays in the site preparation. All aspects of marsh establishment must be an integral part of the design and planning of the total project. Selection of the plant species to be used in the various available elevation zones at the site must be governed by (1) the plant species known to exist within these zones in natural marshes in the region, (2) the objectives of the project, (3) the relative growth rates and sediment stabilizing capabilities of the candidate plants, and (4} the relative food value ratings of the candidate plants stock that can be successfully used at the site will depend upon (1) the available surface elevations at the site, (2) the exposure of the site to various physical stresses, and (3) the time of planting. Properly developed nursery stock is considered superior to all other types for sites or sections of sites subjected to high wave and debris deposition stresses and for summer, fall, and winter plantings. Marsh establishment by seeding is considered feasible only in the spring, in sheltered or confined areas and at elevations above mean tidal level (MTL) (preferably the upper 20% of the mean tidal range). Although exceptions are discussed, a rule of thumb is that increasing the maturity of nursery transplant materials upon decreasing the elevations in the tidal zone will lead to the greatest survival of transplants and the best overall plant establishment. Transplant spacing and fertilization requirements are discussed. Although fertilizations should be conducted for all marsh establishment work in sand sediments, the need for such fertilizations in other sediment types (silt-clay) is not readily determined. Three principal maintenance and management requirements for marsh establishment determined by the study are (1) removal of debris and litter depositions, (2) protection against waterfowl depredation, and (3) fertilization . During the growing season, particularly for late spring and summer plants, algae, submerged aquatic plants, free- floating aquatic plants, and/or sundry debris that have been washed and deposited throughout the developing marsh, may have to be periodically removed. Otherwise, the affected plants may be seriously impaired. Depending upon the prevailing populations of geese, and to a lesser extent other wildlife, marsh establishment sites may have to be protected by enclosures or other effective devices. Areas of marsh establishment sites subject to extended periods of high wave stress may require annual maintenance fertilizations to prevent the marsh from succumbing to the stress. |
Rights: | Approved for public release; distribution is unlimited. |
URI: | http://hdl.handle.net/11681/4738 |
Appears in Collections: | Contract Report |
Files in This Item:
File | Description | Size | Format | |
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CR-D-77-3.pdf | 24.8 MB | Adobe PDF | ![]() View/Open |