GCPO Medium Low Gradient Streams and Rivers - Landscape Endpoints v. 20160609

Jun 9, 2016 (Last modified Jun 13, 2016)
Uploaded by Yvonne Allen
This item is included in Data Basin, but has not been added to the Gulf Coastal Plains and Ozarks LCC CPA.
The Adaptation Science Management Team adopted the broadly defined habitat type of “medium-low gradient rivers and streams,” as a priority habitat within the GCPO geography.  The desired landscape endpoint for these rivers and streams should characterize a natural system in a least impacted condition – systems in this condition should be targets for protection and the goal of restoration activities in degraded systems.  Landscape endpoints specified in the GCPO Integrated Science Agenda (ISA) are intended to more narrowly describe localized stream amount, configuration and condition.  In the ISA, a general description of desired landscape endpoints for medium-low gradient streams and rivers include intact channel morphologies that support riffles and pools and a complex of physical structure (woody debris, leaf litter, and substrate types).  Flows should be relatively steady, with infrequent periods of low water quantity.  Hydrology for a given reach should be closest to the most natural hydrology given its landscape position.  Many of these waters will be primarily composed of organisms adapted to warmwater conditions, but water quality should not lead to lethal conditions for warm water communities.
Gradient threshold definitions were adapted from those established by SARP.  Original drafts of this habitat assessment used a slope threshold of less than 0.02 (meters/meters) based on the “SLOPE” attribute for each stream segment reported in the NHDPlus v2 attribute table.   Current iterations of the assessment instead use elevation less than 130m (MINELEVSMO > 130 in NHDPlusv2) to distinguish this habitat from upland streams which are primarily located in the Ozarks.  
Throughout this analysis, the medium resolution NHD plus v2 was adopted for direct and indirect estimates of many landscape endpoints.  These data were relied upon because they provide complete publicly available coverage throughout the GCPO geography.   The data are, however, only as good as the USGS topographic data sheets upon which they are based.  Inaccuracies arise due to a variety of factors including actual change in stream configuration since the data were created or overgeneralization due to the scale at which the data were created.  Inaccuracies may also be the result of inconsistency in flowline delineation between topographic data sheets or misinterpretation of flow pathways, particularly in areas having low relief and abundant barriers to flow. 
Further details may be found in the Draft Medium-Low Gradient Ecological Assessment.
Freshwater Aquatic: Medium-low gradient streams and rivers Landscape Endpoints
Amount:  Maintain current river miles
Configuration:  Connectedness that ensures accessibility of habitats and resources within a watershed
Lateral connectedness: functional connectivity to floodplain habitats
Linear connectedness: functional connectivity of a stream network
                        Temperature – below critical threshold
Adequate magnitude with limited frequency of low flows      conditions
                        Intact channel morphologies 
Natural riffle-pool sequences
Meandering channels with natural sinuosity   
                        High physical structure complexity 
                                    High amounts of small woody debris
                                    Adequate amounts of large woody debris
                                    Diversity of substrates, including numerous gravel                            beds and sandbars
Data Provided By:
Gulf Coastal Plains and Ozarks LCC Staff

National Hydrographic Dataset (NHDPlus v2)

EPA StreamCat Database
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About the Uploader

Yvonne Allen
with USFWS

Ecologist / Aquatic Resources Analyst