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Summarize overall biological, chemical and physical functions being performed:
<br />C. SIGNIFICANT NEXUS DETERMINATION
<br />A significant nexus analysis will assess the flow characteristics and functions of the tributary itself and the functions performed b}~ any
<br />wetlands adjacent to the tributary to determine if they significantly affect the chemical, physical, and biological integrity of a TNW.
<br />For each of the following situations, a significant nexus exists if the tributary, in combination with all of its adjacent wetlands, has more
<br />than a speculative or insubstantial effect on the chemical, physical and/or biological integrity of a TNW. Considerations when
<br />evaluating significant nexus include, but are not limited to the volume, duration, and frequency of the flow of water in the tributary and
<br />its proximity to a TNW, and the functions performed by the tributary and all its adjacent wetlands. It is not appropriate to determine
<br />significant nexus based solely on any specific threshold of distance (e.g. between a tributary and its adjacent wetland or between a
<br />tributary and the TNW). Similarly, the fact an adjacent wetland lies within or outside of a floodplain is not solely determinative of
<br />significant nexus.
<br />Draw connections between the features documented and the effects on the TNW, as identified in the Rapanos Guidance and discussed in
<br />the Instructional Guidebook. Factors to consider include, for example:
<br />• Does the tributary, in combination with its adjacent wetlands (if any), have the capacity to carYy pollutants or flood waters to TNWs, or to
<br />reduce the amount of pollutants or flood waters reaching a TNW?
<br />• Does the tributary, in combination with its adjacent wetlands (if any), provide habitat and lifecycle support functions for fish and other
<br />species, such as feeding, nesting, spawning, or rearing young for species that are present in the TNW?
<br />• Does the tributary, in combination with its adjacent wetlands (if any), have the capacity to transfer nutrients and organic carbon that
<br />support downstream foodwebs?
<br />• Does the tributary, in combination with its adjacent wetlands (if any), have other relationships to the physical, chemical, or biological
<br />integrity of the TNW?
<br />Note: the above list of considerations is not inclusive and other functions observed or known to occur should be documented below:
<br />1. Significant nexus findings for non-RPW that has no adjacent wetlands and flows directly or indirectly into TNWs. Explain findings of
<br />presence or absence of significant nexus below, based on the tributar}~ itself, then go to Section IILD:
<br />The d-~~ washes would be impacted in the upper reaches of drainage basins in the East Salt Creek Drainage (ESCD). The ESCD
<br />draiuage receives most of its flow volume from spring snow melt in the Book Cliffs and the impacted project area represents a small
<br />portion, less than 3%, of the total drainage area. There is no surface water connection to RPW's and the OHWM is discontinuous and
<br />inconsistent in drainage channels. Variations in precipitation intensity and spatial distribution further decrease the ability of the
<br />washes to transfer nutrients, sediment, or pollution to down stream RPW's. No aquatic species are supported by the washes within the
<br />project area, however, incidental use by terrestrial species characteristic of the salt desert shrub community occurs.
<br />Based on the information provided in Section III, B-1 above, tributaries within the proposed project impact area were found to have an
<br />insignificant and speculative impact on the physical, chemical, and biological of the down stream TNW (Colorado River) or its RPW
<br />tributaries. There is no information available to show that these washes: 1) is or could be used by interstate or foreign travelers for
<br />recreational or other purposes, 2) produces fish or shellfish which are or could be taken and sold in interstate or foreign commerce, or
<br />3) is or could be used for industrial purposes by industries in the interstate commerce
<br />Significant nexus findings for non-RPW and its adjacent wetlands, where the non-RPW flows directly or indirectly into TNWs.
<br />Explain fmdings of presence or absence of significant nexus below, based on the tributary in combination with all of its adjacent wetlands,
<br />then go to Section IILD:
<br />3. Significant nexus findings for wetlands adjacent to an RPW but that do not directly abut the RPW. Explain findings of presence or
<br />absence of significant nexus below, based on the tributary in combination with all of its adjacent wetlands, then go to Section IILD:
<br />D. DETERMINATIONS OF JURISDICTIONAL FINDINGS. THE SUBJECT WATERS/WETLANDS ARE (CHECK ALL THAT
<br />APPLY):
<br />TNWs and Adjacent Wetlands. Check all that apply and provide size estimates in review area:
<br />^ TNWs: linear feet width (ft), Or, acres.
<br />^ Wetlands adjacent to TNWs: acres.
<br />2. RPWs that flow directly or indirectly into TNWs.
<br />^ Tributaries of TNWs where tributaries typically flow year-round are jurisdictional. Provide data and rationale indicating that tributary
<br />is perennial:
<br />^ Tributaries of TNW where tributaries have continuous flow "seasonally" (e.g., typically three months each year) are jurisdictional.
<br />Data supporting this conclusion is provided at Section IILB. Provide rationale indicating that tributary flows seasonally:
<br />WestWater Engineering Page 21 of 23 COE Jurisdictional Determination Request
<br />DBMS 41
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