ERDC/CRREL CR-10-3
Growing Season Definition and Use in Wetland Delineation: A Literature Review
by Karen Malone and Hans Williams
ABSTRACT: The definition of growing season in the 1987 U.S. Army Corps of Engineers Wetland Delineation Manual is derived from the soil biological-zero temperature concept. Lacking direct information on soil temperatures, minimum air temperature thresholds are used as indicators of the beginning and ending dates for the growing season. The 1987 Manual regional supplements allow for field observations of above-ground plant growth to estimate the growing season period. Since acceptance of the 1987 Manual, the growing season concept has been controversial. Soil biological zero does not apply to large areas of the continental United States, minimum air temperature thresholds appear inconsistent with observations of above- and below-ground biological activity, and photoperiodism and thermoperiodism result in local, regional, and annual variations for determining the growing season period based on plant activity. Additionally, the belief that wetlands perform ecological functions year round supports the argument that defining the growing season is irrelevant. A literature review of the environmental factors that influence above- and below-ground biological activity is presented. Recommendations are made on the use of the growing season concept to support jurisdictional wetland delineation determinations.
If you wish to access/download the document (383 kb) in pdf format, the address is: http://libweb.wes.army.mil/uhtbin/hyperion/CRREL-CR-10-3.pdf
This is a great intro for the budding environmental engineer. At some point, you’ll have to get muddy to really understand wetlands though.
Wetland Delineation 1
Wetland Delineation 2
We wanted to shine a spotlight today on a new solution from CorpsJD, a newly launched online GIS GPS-Capable Wetland Delineation, Mapping & Reporting Software Service. Built on the Microsoft platform of Windows Server 2008, SQL Server 2008, and Bing maps, and integrated with ESRI’s GIS application, CorpsJD provides a high performance and reliable service that simplifies the environmental assessment and permitting process associated with wetland properties. In the words of CorpsJD, “Imagine if you could instantly load Bing aerial maps and see your property’s aquatic constraints, soil concerns, FEMA floodplains and other state and local environmental variables that determine a properties net worth. That’s CorpsJD. All of this is displayed in a standardized GIS mapping format that’s easy to learn, all at the click of a mouse. Imagine saving 50% of the field time and 80% of the office time on a job you’re doing anyway.” CorpsJD is hosting a series of webinars introducing the new features and functionality of the service. Find out more at http://www.corpsjd.com
A free hydric soils identification book is available online. Click the link. Enjoy.
Congaree National Park to sponsor delineation training | Columbia, SC News.
Wetland Delineation Training
Columbia, South Carolina
November 16 – 20, 2009
Discover Columbia, SC and Congaree National Park. Join us for Swamp School in beautiful downtown Columbia. The Columbia Conference Center is easily accessible and features onsite parking and in-house catering. Our field work will take us to Congaree National Park, home to the largest remnant of old-growth floodplain forest remaining on the continent. Experience national and state champion trees, towering to record size amidst astonishing biodiversity.
Accurate wetland delineations are a necessity for many types of land use projects. When you need to expand your business capabilities and hone your skills, this intensive combination of classroom and field training will teach you what you need to know and provide valuable hands-on delineation experience. This traditional 38-hour (4½-day) wetlands delineation class covers the current and proposed USACOE wetlands delineation methods as well as the recent Rapanos decision and the new regional supplements.
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1-877-479-2673 for more info.
The California State Water Resources Control Board is considering a proposed definition of “wetlands” that could significantly expand the state’s regulatory jurisdiction beyond the longstanding federal definition administered by the United States Army Corps of Engineers. State Wetland Policy Historically, the State and Regional Water Boards have relied primarily on the federal Clean Water Act program to protect wetlands. But in response to a series of Supreme Court decisions limiting the scope of federal wetland jurisdiction, the State Board has acted to regulate wetlands under state law in order to “fill the gap” created by receding federal jurisdiction. As part of this effort, the State Board directed its staff in April 2008 to develop a wetlands and riparian policy to strengthen the protections for wetlands and water quality. The first phase of this policy is directed at wetland impacts from dredge and fill activities and seeks to: (1) create a state wetland definition that “would reliably define the diverse array of California wetlands based on the United States Army Corps of Engineers’ wetland delineation methods to the extent feasible”; (2) develop a mechanism to regulate activities in wetlands, based on existing federal guidelines requiring the avoidance of wetland impacts to the extent practicable; and (3) identify wetland assessment methods to evaluate the efficacy of wetland regulatory programs. Later phases of the wetland policy will seek to expand wetland protections to reach “other activities” that do not involve dredging or filling a wetland and, ultimately, to reach activities occurring in riparian areas adjacent to wetlands. Proposed Wetland Definition To implement the first phase of its wetland policy, the State Board convened an independent Technical Advisory Team, which determined that the existing wetlands definitions — including the long-established Corps definition used by the State Board for decades — were not broad enough to capture all areas that provide wetland functions, such as certain un-vegetated areas like mudflats and tidal pools. On September 25, 2009, the State Board released for public review the team’s proposed definition which provides: An area is a wetland if, under normal circumstances, it (1) is saturated by ground water or inundated by shallow surface water for a duration sufficient to cause anaerobic conditions within the upper substrate; (2) exhibits hydric substrate conditions indicative of such hydrology; and (3) either lacks vegetation or the vegetation is dominated by hydrophytes. At first glance, this proposed definition appears to rely on the same three factors that the Corps has long used to distinguish wetlands from non-jurisdictional uplands: wetland hydrology, wetland soils and wetland vegetation. However, the proposed state definition differs from the Corps’ definition in a number of important ways: • Wetland Hydrology: Under the proposed definition, the presence of wetland hydrology would be presumed in most California environments whenever an area is wet for seven consecutive days. This contrasts with the Corps’ approach, which requires a showing that an area is, under normal circumstance, saturated for at least 14 consecutive days annually. As a result, application of the proposed state definition could greatly expand the amount of land in California that is deemed to have the requisite wetland hydrology. • Wetland Soils: The proposed state definition would replace the Corps’ requirement that an area have hydric soils with the new requirement that an area exhibit “hydric substrate conditions.” The meaning of this change is uncertain, however, since the term “hydric substrate” is not clearly defined. Read broadly, the definition could be interpreted as removing the requirement that wetlands have hydric soils. • Wetland Vegetation: Under the proposed definition, an area can be considered a wetland when it either has hydrophitic vegetation or lacks vegetation. This contrasts with the Corps’ definition, which requires the presence of wetland vegetation. This change is intended allow the state to classify mudflats and tidal pools as wetlands, but it may also have unintended consequences, by regulating areas such as cropped agricultural fields that provide no wetlands functions. The State Board has not yet set a date for when it will consider formal adoption of a new wetland definition, although it previously indicated its goal to adopt a such a definition in 2009. Potential Significance of Expanded Definition If the Board adopts the proposed definition, it would go far beyond merely filling the gap created by the Supreme Court decisions limiting federal wetland jurisdiction. Indeed, the new definition could cover areas never previously regulated as wetlands under federal or state law. Because the definition departs significantly from the Corps’ longstanding program, it also may require landowners and developers to conduct two separate wetland delineations for the same piece of land—one for the Corps using the traditional definition, and one for the state using an expanded definition. To date, neither the California State Board nor the Team has provided the scientific basis for the Team’s conclusion that its dramatic changes to the Corps’ definition are needed to protect wetlands. Accordingly, it is impossible to determine at this juncture whether these changes, and the increased regulatory burdens they could create, will in fact serve to enhance water quality or the environment.