David Magney Environmental Consulting

Wetland Delineation

Wetland Delineations

Wetlands are habitats that are permanently or seasonally flooded, ponded, or saturated during a substantial period of time, and meet specific conditions.   Wetlands include habitats such as marshes, streams, riparian areas, ponds, vernal pools, seeps, intertidal zones, fens, bogs, and similar habitats.   Nearly all wetlands are considered waters of the United States, and in California, waters of the state. Most activities that humans want to do in wetlands require a permit from one or more regulatory agencies.   The U.S. Army Corps of Engineers (Corps) has jurisdiction over all waters of the U.S., including wetlands.   The Corps issues permits for a wide variety of activities proposed within their jurisdiction.   All activities within waters of the State of California are regulated by the State Water Resources Control Board pursuant to Section 401 of the federal Clean Water Act and/or the California Department of Fish and Game pursuant to Section 1600 et seq. of the California Fish and Game Code.

A wetland delineation is used to formally determine the jurisdictional boundary for the Corps.   Actually, it is the Corps' responsibility to delineate their jurisdiction; however, due to severe understaffing as a result of underfunding, you will possibly have to wait over a year before the Corps will be able to come and delineate your property to determine the extent of their jurisdiction.   However, the Corps allows consultants to do this on their behalf according to specific methodology (Corps Wetland Delineation Manual). After a consultant-prepared delineation is submitted to the Corps, the Corps will "verify" the delineation formally.   In most cases, the Corps will require a wetland delineation before issuing a permit to fill a wetland, or part of a wetland.  

A Corps wetland must meet three specific criteria before being considered a jurisdictional wetland: presence of and predominance by hydrophytic (water-loving) vegetation, hydric soils (soils regularly flooded or saturated), and wetland hydrology.   Corps waters of the U.S. are areas that regularly convey or hold water, with some exceptions.   Following the methods described in the Corps' 1987 Manual is necessary to determine which areas are considered jurisdictional wetlands.   The Corps is preparing regional delineation manuals to take into consideration regional characteristics.   The arid areas of the Southwestern part of the United States is one such region, with the Corps issuing and requiring the use of this regional delineation manual for areas in the Arid Southwest, including southern California.   A notice from the Corps about the regional delineatino supplement is available at the Corps' Los Angeles District website.   Mr. Magney assisted the Los Angeles District of the Corps with field-testing this regional manual. A copy of the Arid Southwest delineation supplement is available here.

While the California Coastal Commission and California Department of Fish and Game also regulate activities in wetlands in California, neither agency has a formal manual or methodology established to determine the extent of their jurisdiction.   Both these California agencies have their own definitions of a wetland, and specific regulations they are entrusted with implementing and enforcing.   Basically, the presence of any one of the three criteria used by the Corps is enough to determine whether a site has wetlands as defined by the State of California.   However, since California lacks a manual, use of the Corps' manual is generally an accepted method to determine a wetland according to the California definition.

DMEC has extensive experience conducting wetland delineations, particularly using the Corps Manual.   DMEC staff have been trained in federal wetland delineation and related areas, such as in hydric soils and wetland plant identification.   DMEC has helped the Corps field test a new version of the Corps Manual for use in the arid Southwest.   DMEC's wetland delineations are highly regarded by the Corps and routinely accepted and verified as submitted.   DMEC assisted the Ventura County Planning Division (VCPD) with a booklet, Wetland Project Permitting Guide, describing wetland jurisdiction by various agencies, which is available at VCPDs website.

DMEC wetland delineations can be viewed for several projects from the link to DMEC's Reports page that includes copies of the delineations for the Lyons Canyon Ranch and Centex projects, providing examples of both simple and complex delineations.   A map of a relatively simple wetland delineation performed in the Ojai Valley is available here.   DMEC staff have performed numerous wetland delineations throughout California.

This page last updated 9 May 2007
& Staff
Client List
Contact Us

Mission Statement:
To provide quality environmental consulting
services with integrity that protect and enhance
the human and natural environment.
Home | Qualifications & Staff | Client List | Projects | Reports | Presentations | Contact Us