A Field Guide to the Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United States: A Delineation Manual

U.S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory | August 1st, 2008


The Ordinary High Water Mark (OHWM) is an approach for identifying the lateral limits of non-wetland waters. However, determining whether any non-wetland water is

A Guide to Ordinary High Water Mark (OHWM) Delineation for Non-Perennial Streams in the Western Mountains, Valleys, and Coast Region of the United States

U.S. Army Corps of Engineers (USACE) | August 14th, 2014


Federal regulations define the ordinary high water mark (OHWM) as “that line on the shore established by the fluctuations of water and indicated by physical cha

A Path Forward for California’s Freshwater Ecosystems

Public Policy Institute of California (PPIC) | December 2nd, 2019


Californians rely on freshwater ecosystems for many things: water supply, hydropower, recreation, fisheries, flood risk reduction, biodiversity, and more. These ecosystem

An Index of Biotic Integrity (IBI) for Perennial Streams in California’s Central Valley

California State Water Resources Control Board | December 1st, 2008


Bioassessment is the science of using aquatic organisms as indicators of ecological condition in streams in rivers. Many types of organisms can be used as indicat

Assessing the Health of Southern California Streams

California State Water Resources Control Board | April 14th, 2011


There are over 4,200 miles of perennial streams in the coastal watersheds of Southern California. Effective protection and management of these resources require an unders

Assessing the presence of current-use pesticides in mid-elevation Sierra Nevada streams using passive samplers, California, 2018–19

U.S. Geological Survey (USGS) | February 9th, 2023


Passive sampler devices were deployed in six northern California streams five times between November 2018 and December 2019 to measure the presence or absence of current-

Bathymetry and Digital Elevation Models of Coyote Creek and Alviso Slough, South San Francisco Bay, California

U.S. Geological Survey (USGS) | March 15th, 2018


In 2010 the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center completed three cruises to map the bathymetry of the main channel and shall

Benthic Invertebrate and Deposited Sediment TMDL Guidance for the Pajaro River Watershed

California State Water Resources Control Board | March 1st, 2016


The Pajaro River and its tributaries are exposed to sediments from a variety of sources. To establish limits for regulating this pollutant, it is necessary to u

Biological Condition of Non-Perennial Streams and Spring-Fed Oases in the Colorado River Basin Region

California State Water Resources Control Board | August 22nd, 2014


The Colorado River Basin Regional Water Board conducted bioassessment sampling at high-quality (i.e., “reference”) streams in their region during 2013-2015. The purpo

Biology-based Stressor Thresholds

California State Water Resources Control Board | October 1st, 2011


The objective of this memo is to describe how biological assessment data (such as those collected using Surface Water Ambient Monitoring Program (SWAMP) bioasse

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