EPA-OW: NRSA Habitat 2009 (Boat): Physical Habitat Characterization in large non-wadeable rivers
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Official Method Name
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Section 5.2: Physical Habitat Characterization in Non-Wadeable Rivers and Streams (of National Rivers and Streams Assessment: Field Operations Manual (2009)) |
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Current Revision
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Media
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WATER (Waterbody type - Non-wadeable stream) |
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Instrumentation
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Field Equipment |
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Method Subcategory
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Physical |
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Method Source
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Citation
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Protocol
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EPA-841-B-07-009 - National Rivers and Streams Assessment: Field Operations Manual (2009) |
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Brief Method Summary
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The protocol defines the length of each sampling reach proportional to river wetted width and then systematically places measurements to statistically represent the entire reach. Stream thalweg depth measurements, habitat classification, and mid-channel substrate observations are made at very tightly spaced intervals; whereas channel “littoral” and riparian stations for measuring or observing substrate, fish cover, large woody debris, bank characteristics and riparian vegetation structure are spaced further apart. The tightly spaced depth measures allow calculation of indices of channel structural complexity, objective classification of channel units such as pools, and quantification of residual pool depth, pool volume, and total stream volume. Field data collection for the physical habitat assessment is accomplished in a single float down each sampling reach. River sample reach lengths are defined as 40 x the wetted width at the x-site, with a minimum of 150m and maximum of 4km. To characterize mid-channel habitat (Table 5.2.2), they measure a longitudinal thalweg (or mid-channel) depth profile, record the presence of snags and off-channel habitats, classify main channel habitat types, characterize mid-channel substrate, and locate the 11 transect locations for littoral/riparian sampling and other habitat observations. At each of the 11 transects (A-K), they measure channel wetted width, bankfull channel dimensions, incision, GPS lat/long, and then assess near-shore, shoreline, and riparian physical habitat characteristics by measuring or observing littoral depths, riparian canopy cover, substrate, large woody debris, fish cover, bank characteristics, riparian vegetation structure, presence of large (“legacy”) riparian trees, non-native riparian and aquatic species, and evidence of human activities. After all the thalweg and littoral/riparian measurements and observations are completed, the crews estimate the extent and type of channel constraint. |
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Scope and Application
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This method describes the procedure for collecting water quality, physical habitat characteristics in large non-wadeable rivers that are sampled as part of the U.S. EPA's National Rivers and Streams Assessment. Physical habitat in rivers includes all those physical attributes that influence or provide sustenance to river organisms. Physical habitat varies naturally; thus, expectations differ even in the absence of anthropogenic disturbance. Within a given physiographic-climatic region, river drainage area and channel gradient are likely to be strong natural determinants of many aspects of river habitat, because of their influence on discharge, flood stage, and stream power (the product of discharge times gradient). |
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Applicable Concentration Range
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Interferences
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Follow the guidelines for choosing the habitat sampling increment based on channel width to determine the thalweg profile proceedure. |
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Quality Control Requirements
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It may be necessary to set up intermediate (supplemental) slope and bearing points between a pair of cross-section transects if you do not have direct line-of-sight along (and within) the channel between stations. |
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Sample Handling
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Maximum Holding Time
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Relative Cost
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Unknown |
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Sample Preparation Methods
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