WEBVTT

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Hello . Welcome to an introduction to

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the ordinary high watermark National

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Manual . My name is dr Gabrielle David .

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I'm a researcher from the U . S . Army

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Engineering research and development

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center , cold regions research and

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engineering laboratory . Today I'm

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going to talk to you about the release

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of the interim draft for the National O .

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H . W . M . Field delineation manual

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for rivers and streams . I'll give you

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an introduction to the ordinary high

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watermark and provide background on the

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information you can find in the new

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National Manual .

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The National Manual was released as an

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interim version on November 30 , 2020

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to the US Army Corps of Engineers and

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Environmental Protection Agency are

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requesting feedback from uses districts ,

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practitioners and the public through

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December 1 , 2023 . The National

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Technical Committee for O . H . W . M .

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A group composed of E . P . A Army corp

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regulators . Ergic researchers and

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academics plan to incorporate feedback

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into the final version so that we can

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make sure that this is a document ,

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field procedure and data sheet That is

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helpful as possible for the

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practitioners in the field .

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The National Manual divides the country

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into eight regions including the

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Northwest , southwest Northern prairies ,

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southern prairies , northeast ,

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Southeast Alaska and Hawaii case study

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data were collected from each of these

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regions to include in the National

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Manual . The stars on the map show the

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locations of the case studies .

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So what does the ordinary high

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watermark mean ? The regulatory

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definition states that line on the

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shore established by the fluctuations

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of water and indicated by physical

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characteristics such as a clear natural

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line impressed on the bank , shelving

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changes in the character of soil

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destruction of terrestrial vegetation .

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The presence of litter and debris or

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other appropriate means that consider

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the characteristics of the surrounding

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areas Along with the definition of

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ordinary high watermark found in the

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Clean Water Act . We also have

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additional guidance from the regulatory

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guidance letter 0505 . The guidance

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letter describes a few other physical

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characteristics such as vegetation ,

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matted down , bent or absent sediment

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sorting , leaf litter , disturbed or

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washed away , scour deposition ,

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multiple observed flow events , water

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staining staining , changing plant

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community . These characteristics can

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all be important to identify but what

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do these physical characters that look

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like in different stream systems or how

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and when are they related to ? O . H .

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W . M . Is not described any further .

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Therefore , National Manual was needed

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to provide more information about these

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physical characteristics in the

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relationship to the ordinary high

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watermark , streams and rivers around

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the US come in all sorts of shapes and

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sizes , depending on the climate ,

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geology and topography of the location .

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Therefore the physical characteristics

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that are indicators of the ordinary

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high watermark can look very different

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in these different environments . And

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National Manual is needed to provide

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more information on how to investigate

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sites for the H . W . M . And the

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differences in physical characteristics

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in these different environments . The

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overarching goal of the National Manual

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is to provide tools and supporting

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documentation to perform accurate ,

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consistent and scientifically based O .

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H W . M delineations . I'm going to

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outline five goals in the National

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Manual and discuss how we address each

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of these within the manual . Therefore

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the goals of the National manual are to

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first provide consistent science based

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definitions of O H W M indicators .

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Second outline a clear decision making

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process using the weight of evidence

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approach , which I will talk about in a

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little bit . Third provide a forum for

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rapid and consistent field data

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collection . Fourth described landscape

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scales , considerations for O H W . M .

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Interpretation and five provide

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examples of case studies for difficult

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O H W . M delineations . The next set

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of sides go over each of these goals in

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detail . The first goal

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is to provide science based definitions

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of O H W . M indicators to do this .

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It's important to understand the

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hydrology of a stream system so that

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practitioners can go out and identify

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which indicators are related to high

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flows versus low flows . The National

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Manual discusses in detail the types of

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flows found in a stream to the right

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here is an example of a survey stream

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cross section . I'm gonna show you how

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flows can be over land and help with

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understanding which part of the cross

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section is likely to have O H W . M

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indicators . This cross section , for

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instance shows low or base flow up to

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this elevation , that elevation is the

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mean annual flow boundary above that is

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uh some moderate flows and then you

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start to get into the high flows . Now

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we're looking for the ordinary high

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watermark . So you would expect to find

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that in the part of the cross section

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that's inundated by high flows uh

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above there you have extreme flows

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which can continue to rise up and

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spread out over the hill slope or flood

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plain , uh depending on how big a flow

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it is , an extreme flows or flows that

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really substantially alter the cross

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section and the equilibrium state of

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the channel methods for developing

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these cross sections and flow

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visualizations at a site are described

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in detail in the manual and in an

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accompanying report , the hydrologic

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analysis of field delineated O H W . M .

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For rivers and streams . The flow

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visualizations are provided to help

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regulators the public understand again

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where you're likely to find low flow

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indicators versus where you would be

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finding high flow indicators .

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To better understand how physical

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indicators of flow form . It is helpful

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to have a better scientific

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understanding of streams . The O H W .

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M . Is a regulatory boundary , but the

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definition has a lot of similarities to

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other terms . Have been identified and

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defined in scientific literature such

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as bank fel . The National manual

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provides more detail on the definition

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of bank full and active channel and how

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and when these definitions can overlap

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with the H W . M . Before

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moving on . It's important to

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understand how the concept of active

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channel painful and O H . W . M . Are

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defined . So first , what is meant by

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active channel . This is a concept that

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is used widely but inconsistently . Uh

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Generally the phrase has been used to

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denote the unvetted stated portion of

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the channel or describe the section of

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channel below which bank slopes deeply .

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These two interpretations can result in

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very different portions of the channel

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being identified as the actor channel .

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Therefore , we outlined three primary

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criteria uh to distinguish the actor

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channel in the national manual , uh

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generally having to do with the portion

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of the valley bottom that has uh

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erosion and additional features created

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by ongoing river processes . Uh The

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upper elevation limit , which water is

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contained within a channel or the

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portion of channel without mature woody

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vegetation . Uh The first criteria can

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be very useful when looking at braided

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and multi thread systems where there's

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a lot of uh channel bars and a lot of

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secondary channels . So you're really

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looking at that portion of the valley

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that's being reworked by those river

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processes . The second criteria can be

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helpful when identifying the top of

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bank as an active channel but can be

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problematic and for instance , deeply

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incised systems where you wouldn't

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identify the top of that embankment .

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For instance , in this picture as the

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active channel . The third criteria can

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be useful uh in certain regions of the

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country , but in other climatic regions

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there's such as the southeast , there

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are woody species that grow in the

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stream bed . And so it's really

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important to put this channel in the

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landscape context of the region .

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Thinking about land use and vegetation

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and the climate uh when trying to

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identify what you mean by active

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channel . Here are

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three schematics showing different

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channel types to try to demonstrate

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where O . H . W . An active channel can

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overlap and where they may not

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necessarily overlap . And these are

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very simplified examples . So uh it may ,

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there may be cases that in these

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channel types you may not always get

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overlap between where you identify

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Active channel and O H . W . M . But in

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this , in these examples uh in the

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braided anastomosis system , the H . W .

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And Active Channel would very likely be

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in the same location . Whereas in the

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stream wetland complex , there's a low

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flow channel that would most likely be

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identified as the active channel , but

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the H . W . M . The high water marks

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would be above that low flow channel

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system .

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There are very clear connections on how

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being full has been defined over the

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years . And the definition of O . H . W .

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M . The scientific literature contains

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a lot of similar wording , such as

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natural line and pressed on the banks

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transitions in soil and vegetation and

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presence of litter and debris .

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Therefore the indicators of O . H . W .

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M . Are similar to stream

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characteristics used to identify bank

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full in the National manual , we broke

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up these physical characteristics into

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four categories of geum or thick

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vegetation , sediment and ancillary

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indicators here we are just showing

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some examples of what types of physical

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characteristics can be found under each

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categories , such as break in slope ,

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under geum or fick , lower limit of

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mature . What do you , perennial

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vegetation under vegetation , change in

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sediment texture under soil , under

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sediment or racking presence of organic

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litter or large . Would deposition

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under ancillary

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key points to remember about the

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science of O H . W . M . R . First that

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river and stream morphology czar shaped

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by relatively infrequent flows that

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typically occur on the order of several

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times per year to several times per

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decade . Therefore the H . W . M . Is

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shaped and maintained by flows that are

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well above mean annual flow but are not

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extreme . These are flows that maintain

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but do not substantially alter channels ,

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geometry or location . The relationship

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between stream flow and stream

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characteristics are highly variable in

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space and time . No single recurrence

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and roll hydrologic statistic has the

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same geographic significance in all

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systems . So the H . W . M . Is not

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defined by specific stream flow

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recurrence interval such as a two year

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flood or fire five year flood , but it

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can be hydra logically constrained

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within a general range of recurrence in

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a role similar to bank , full flows and

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bank , full stage and the actual active

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channel limits our scientific

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counterparts . The regulatory concept

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of O H . W . M .

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Therefore O H . W . M . Delineations

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should utilize robust robust indicators

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of recurring high flows .

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The second goal of the manual is to

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outline a clear decision making process

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Using the weight of evidence procedure .

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The weight of evidence procedure is a

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logical process that provides a clear

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methodology for assembling evidence ,

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evaluating awaiting the evidence and

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integrating different lines of evidence

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to come to a scientifically supported

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conclusion . The method provides a way

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to determine the significance of

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observations and to combine

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observations to arrive at this

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conclusion . Many may find that they

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already followed this logical process

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but just didn't have it outlined in a

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clear step by step way to follow this

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methodology . First , you assemble

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evidence . Many of the indicators that

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are listed as evidence of O H W . M .

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Are simply characteristics of stream

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flow and depending on hydrologic land

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use and geologic context of the system

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may be related to low flow high floor

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extreme flows . Therefore , the first

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step is to understand where these

12:15.966 --> 12:18.077
indicators exist . The example on the

12:18.077 --> 12:20.243
right here shows where they're geum or

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fick vegetation and sediment indicators

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on this cross section . The next step

12:24.670 --> 12:26.837
is to weight the evidence by assessing

12:26.837 --> 12:29.003
the strength and relative relevance of

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each line of evidence . The flow shown

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in the photograph and on the cross

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section is a low flow which is known

12:35.170 --> 12:36.948
from the USgs stream gauge data

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upstream . Therefore , the indicators

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near the low flow elevation are not

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relevant lines of evidence . These are

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obviously not high flow indicators .

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The third step is to weigh the body of

12:48.227 --> 12:50.550
evidence . This is logically combining

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where high flow indicators occur up and

12:52.772 --> 12:54.772
downstream and determining the most

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likely elevation of the H . W . M .

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From the combination of indicators

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to better understand how to weigh the

13:04.050 --> 13:06.050
body of evidence . So combining the

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high flow indicators up and downstream .

13:08.328 --> 13:10.550
Here's a schematic of the same stream ,

13:10.550 --> 13:13.420
a simplified one of this site to be

13:13.420 --> 13:15.990
able to see the indicators that were

13:15.990 --> 13:18.212
observed up and downstream and not just

13:18.212 --> 13:21.250
at the cross section . So here on the

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left is the site at low flow and on the

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right is the site with a hypothetical

13:25.583 --> 13:28.360
hypothetical ordinary high water level

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connecting the flow indicators up and

13:31.090 --> 13:34.210
downstream . So here the cut bank at

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the top of the figure is connected with

13:37.220 --> 13:39.490
the at the same elevation of the

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sandbar and where sand and claire

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getting mixed on the cut bank at the

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bottom of the figure , ah This also

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inundates completely the gravel bar on

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the opposite side of the stream .

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Therefore , the top of the bank at the

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top of that cut bank , the upper

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elevation the sandbar and transition to

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woody vegetation , where all lines of

14:05.267 --> 14:07.433
evidence that are combined to conclude

14:07.433 --> 14:09.322
that this is the elevation of the

14:09.322 --> 14:10.767
ordinary high watermark .

14:13.830 --> 14:15.941
The third goal of the National Manual

14:15.941 --> 14:17.886
is to provide a form for rapid and

14:17.886 --> 14:20.052
consistent field data collection . The

14:20.052 --> 14:22.052
National Manual provides a two page

14:22.052 --> 14:24.850
delineation data sheet and a two page

14:24.850 --> 14:28.500
field proceed . These are provided to

14:28.500 --> 14:31.590
help with being able to apply the

14:31.590 --> 14:33.950
scientific understanding of streams as

14:33.960 --> 14:35.738
well as this weight of evidence

14:35.738 --> 14:38.340
procedure to draw a logical conclusion

14:38.340 --> 14:40.562
as to where the ordinary high watermark

14:40.562 --> 14:44.340
is . This field procedure and data

14:44.340 --> 14:46.550
sheet are particularly helpful when

14:46.550 --> 14:48.883
faced with multiple possibilities for O .

14:48.883 --> 14:50.828
H . W . M . Applying the weight of

14:50.828 --> 14:53.050
evidence method can help with drawing a

14:53.050 --> 14:55.217
logical conclusion as to where the H .

14:55.217 --> 14:57.860
W . M . Is located . To apply this

14:57.860 --> 15:00.480
procedure , The first step is to have

15:00.480 --> 15:02.702
an overview of the site from remote and

15:02.702 --> 15:04.940
online resources . This is done to

15:04.940 --> 15:06.940
provide a landscape context for the

15:06.940 --> 15:09.620
site . The second step is to describe

15:09.620 --> 15:11.842
site conditions during field assessment

15:11.842 --> 15:13.842
assessment . This is the assembling

15:13.842 --> 15:17.830
evidence uh procedure . The next

15:17.830 --> 15:19.552
step is to check boxes next to

15:19.552 --> 15:21.830
indicators used to identify the H . W .

15:21.830 --> 15:24.200
M . This again is part of assembling

15:24.200 --> 15:28.000
the evidence and then it's waiting

15:28.000 --> 15:30.167
each line of evidence and weighing the

15:30.167 --> 15:32.870
body of evidence . This eliminates

15:32.870 --> 15:34.759
helps you by eliminating lines of

15:34.759 --> 15:36.814
evidence that are not relevant . For

15:36.814 --> 15:38.926
instance , lines of evidence that are

15:38.926 --> 15:41.400
obviously connected to low flows rather

15:41.400 --> 15:44.260
than high flows . Step forward is

15:44.260 --> 15:46.371
determining if additional information

15:46.371 --> 15:49.570
is needed . Uh So other resources such

15:49.570 --> 15:51.810
as remote online to tools can help

15:51.810 --> 15:53.810
support information observed on the

15:53.810 --> 15:56.600
ground . And the last step is

15:56.600 --> 15:58.711
describing the rationale for location

15:58.711 --> 16:00.878
of O . H . W . M . This means bringing

16:00.878 --> 16:03.100
together all the information to build a

16:03.100 --> 16:05.378
case for the location of the H . W . M .

16:08.230 --> 16:10.286
Key points about the field procedure

16:10.286 --> 16:12.397
and data sheet are that they're there

16:12.397 --> 16:14.619
to help assemble and list evidence that

16:14.619 --> 16:16.841
they provide a set of questions to help

16:16.841 --> 16:19.008
with trying to understand what are the

16:19.008 --> 16:21.341
signatures of recurring flu real action .

16:21.341 --> 16:23.563
They help with considering the relevant

16:23.563 --> 16:23.470
strength and reliability of each

16:23.470 --> 16:25.580
indicator . So the relevance of an

16:25.580 --> 16:27.191
indicator for instance being

16:27.191 --> 16:29.358
representative of high flow conditions

16:29.358 --> 16:31.136
rather than low or average flow

16:31.136 --> 16:32.913
conditions . The strength of an

16:32.913 --> 16:34.691
indicator is relatively , is it

16:34.691 --> 16:36.636
relatively stable ? I consistently

16:36.636 --> 16:39.600
present and identifiable over time and

16:39.600 --> 16:41.267
the reliability being , is it

16:41.267 --> 16:43.710
representative of recurring flow levels

16:43.710 --> 16:46.600
rather than individual flow events ? So

16:46.600 --> 16:48.980
is it something that is there because

16:48.980 --> 16:51.890
of one extreme flow event ? Or is this

16:51.890 --> 16:54.112
something that's representative of high

16:54.112 --> 16:54.860
flows ?

17:01.990 --> 17:04.046
The next goal of the manuals provide

17:04.046 --> 17:05.990
information on how landscape scale

17:05.990 --> 17:08.046
controls , influence flow indicators

17:08.046 --> 17:10.212
and ultimately can influence O H . W .

17:10.212 --> 17:12.323
M . Interpretations . The overarching

17:12.323 --> 17:14.379
goal is of the manual to provide you

17:14.379 --> 17:16.546
with the best professional judgment to

17:16.546 --> 17:18.712
form accurate and consistent O H . W .

17:18.712 --> 17:20.940
M . Delineation , but you can't

17:20.940 --> 17:22.829
delineate the O H . W . M . In an

17:22.829 --> 17:24.996
informed way without understanding the

17:24.996 --> 17:26.940
basic fundamentals of how flu real

17:26.940 --> 17:28.773
systems work at various scales .

17:28.773 --> 17:30.940
Therefore , information is provided in

17:30.940 --> 17:32.662
the manual on how controls the

17:32.662 --> 17:34.607
landscape scale , influence stream

17:34.607 --> 17:36.607
channel characteristics at a site ,

17:40.040 --> 17:42.040
satellite imagery , lidar and other

17:42.040 --> 17:44.510
spatial data can aid in recognizing

17:44.510 --> 17:46.677
significant controls on channel four a

17:46.677 --> 17:48.843
matter , stream anthropogenic controls

17:48.843 --> 17:51.177
on channel form include dams , culverts ,

17:51.177 --> 17:53.010
bridges and significant land use

17:53.010 --> 17:54.954
changes . Natural controls include

17:54.954 --> 17:57.066
underlying geologic characteristics ,

17:57.066 --> 17:59.200
such exposed bedrock and steep

17:59.200 --> 18:01.144
topographic changes such as valley

18:01.144 --> 18:02.478
slope and confinement .

18:05.580 --> 18:08.200
The manual provides information on how

18:08.200 --> 18:10.590
to find these data and how to interpret

18:10.590 --> 18:14.100
it to either understand a site before

18:14.110 --> 18:17.140
going out to observe , observe it in

18:17.140 --> 18:21.070
person or how to understand what was

18:21.070 --> 18:23.890
seen at the site after uh going and

18:23.890 --> 18:25.370
making observations

18:29.770 --> 18:31.937
combined with this . The final goal of

18:31.937 --> 18:34.048
the manual is to prevent case studies

18:34.048 --> 18:36.214
of places where it may be difficult to

18:36.214 --> 18:38.437
delineate . The O . H . W . M . Provide

18:38.437 --> 18:40.714
examples of how to use other resources ,

18:40.714 --> 18:42.881
such as lidar and satellite imagery to

18:42.881 --> 18:45.103
combine with lines of evidence observed

18:45.103 --> 18:47.270
on the ground . For instance , in this

18:47.270 --> 18:46.880
example of a braided system in

18:46.880 --> 18:49.400
California , the lidar and satellite

18:49.400 --> 18:51.790
imagery show potential locations of

18:51.790 --> 18:55.030
secondary channels that can help to

18:55.030 --> 18:57.197
observe that before heading out to the

18:57.197 --> 19:00.120
site so that those channels can then uh

19:00.130 --> 19:01.880
be investigated in person .

19:04.300 --> 19:06.440
Case studies of stream wetland

19:06.440 --> 19:09.060
complexes show a much more complicated

19:09.060 --> 19:11.060
system where high flow channels can

19:11.060 --> 19:13.480
often be found outside the observed

19:13.490 --> 19:15.434
boundaries of the active channel .

19:20.080 --> 19:22.191
The key points about case studies are

19:22.191 --> 19:24.080
that they provide examples of how

19:24.080 --> 19:26.191
disturbance from either human induced

19:26.191 --> 19:27.802
or natural causes can affect

19:27.802 --> 19:29.858
observations of O . H . W . M . They

19:29.858 --> 19:31.969
provide discussion of complex channel

19:31.969 --> 19:33.802
types , including stream wetland

19:33.802 --> 19:35.969
complexes and beaver metal complexes .

19:36.140 --> 19:38.930
They also show examples of how human

19:38.930 --> 19:41.041
induced disturbances , including flow

19:41.041 --> 19:42.874
regulation , culverts , mining ,

19:42.874 --> 19:44.630
agriculture and livestock and

19:44.640 --> 19:47.960
urbanization can influence flow

19:47.960 --> 19:51.280
indicators and uh what's observed at a

19:51.280 --> 19:54.730
site and also how natural disturbances

19:54.730 --> 19:56.730
including fires and debris flow and

19:56.730 --> 20:00.620
extreme flood flows can alter sites on

20:00.620 --> 20:02.564
this website . You will find other

20:02.564 --> 20:04.398
supporting documents such as the

20:04.398 --> 20:06.231
synthesis report , that provides

20:06.231 --> 20:08.342
further background for the scientific

20:08.342 --> 20:10.453
foundation of the H . W . M . As well

20:10.453 --> 20:12.620
as the hydrologic analysis tech report

20:12.620 --> 20:14.620
that provides more detail about the

20:14.620 --> 20:16.787
flow modeling done on the case studies

20:16.787 --> 20:18.953
that are part of the National Manual .

20:19.860 --> 20:22.360
You can also find other field guides

20:22.360 --> 20:24.249
such as the arid west and western

20:24.249 --> 20:26.360
mountain guides and a field guide for

20:26.360 --> 20:28.360
identifying the upper extent of the

20:28.360 --> 20:30.980
channel . This ladder guide also goes

20:30.990 --> 20:33.212
over the weight of evidence procedure .

20:33.400 --> 20:35.622
The release of the interim draft of the

20:35.622 --> 20:37.622
national manual does not affect the

20:37.622 --> 20:39.844
utility of the current regional O . H .

20:39.844 --> 20:42.011
W . M . Manuals for the arid west , in

20:42.011 --> 20:43.900
the western mountains valleys and

20:43.900 --> 20:46.067
coastal regions . However , the public

20:46.067 --> 20:48.233
and practitioners including persons in

20:48.233 --> 20:50.456
these regions are encouraged to utilize

20:50.456 --> 20:52.678
the National O . H . W . M . Manual and

20:52.678 --> 20:54.789
its accompanying O . H . W . M . Data

20:54.789 --> 20:54.670
sheet during this period . In order to

20:54.670 --> 20:56.726
provide comments and feedback on the

20:56.726 --> 20:57.726
interim draft .

21:04.100 --> 21:06.330
Overall , the National Manual provides

21:06.330 --> 21:08.219
a decision making process , Field

21:08.219 --> 21:10.386
procedure and data , sheep O . H . W .

21:10.386 --> 21:12.140
Delineations . It does this by

21:12.140 --> 21:13.807
providing a better scientific

21:13.807 --> 21:16.090
understanding of O H . W are so similar

21:16.090 --> 21:18.480
to bank fel . The H W . M is associated

21:18.480 --> 21:20.424
with recurring flows that are well

21:20.424 --> 21:22.480
above average but not extreme and is

21:22.480 --> 21:24.702
not defined by specific recurrence in a

21:24.702 --> 21:26.702
role but associated with a range of

21:26.702 --> 21:26.490
recurrence and roles that are

21:26.490 --> 21:29.290
regionally variable . It provides

21:29.290 --> 21:31.179
details on applying the weight of

21:31.179 --> 21:33.346
evidence , procedure with accompanying

21:33.346 --> 21:35.512
field procedure and data sheet ideally

21:35.512 --> 21:37.401
the H . W . M would coincide with

21:37.401 --> 21:39.623
multiple indicators . Although this may

21:39.623 --> 21:41.750
not always be the case , it provides

21:41.750 --> 21:43.972
information on interpreting O . H . W .

21:43.972 --> 21:45.861
M . Indicators based on landscape

21:45.861 --> 21:48.360
context of the site . Remote and online

21:48.360 --> 21:50.510
data can add unique perspective and

21:50.510 --> 21:52.677
information that complements the field

21:52.677 --> 21:55.610
data . And in the National Manual shows

21:55.610 --> 21:57.721
how the remote and online data can be

21:57.721 --> 22:00.320
used . It provides case studies to

22:00.320 --> 22:02.270
better understand how to interpret

22:02.280 --> 22:04.910
indicators at difficult sites , streams

22:04.910 --> 22:07.243
are dynamic in space and time and the H .

22:07.243 --> 22:09.132
W . M . Is ultimately defined and

22:09.132 --> 22:10.910
delineated by physical evidence

22:10.910 --> 22:12.243
observed in the field .

22:15.780 --> 22:17.613
Thank you for joining me on this

22:17.613 --> 22:19.669
introduction to the interim draft of

22:19.669 --> 22:21.502
the O H . W . M . National Field

22:21.502 --> 22:23.391
delineation manual for rivers and

22:23.391 --> 22:25.447
streams . There's currently a public

22:25.447 --> 22:27.613
notice out requesting feedback on this

22:27.613 --> 22:29.836
National manual until december 1st 2023

22:30.060 --> 22:32.282
when reviewing the interim draft of the

22:32.282 --> 22:34.282
National manual . Remember that the

22:34.282 --> 22:36.338
manual does not imply or represent a

22:36.338 --> 22:38.393
change to the definition of ordinary

22:38.393 --> 22:40.504
high watermark or waters the US . Nor

22:40.504 --> 22:42.338
does it change existing guidance

22:42.338 --> 22:44.504
related to the O H . W . M . Instead ,

22:44.504 --> 22:46.449
the National manual provides draft

22:46.449 --> 22:48.393
technical guidance for identifying

22:48.393 --> 22:50.504
aquatic resources that may be subject

22:50.504 --> 22:52.338
to regulatory jurisdiction under

22:52.338 --> 22:54.560
section four or four of the Clean Water

22:54.560 --> 22:56.560
Act and sections nine and 10 of the

22:56.560 --> 22:58.616
rivers and Harbors Act of 18 99 . It

22:58.616 --> 23:00.504
does this by providing a standard

23:00.504 --> 23:02.393
process , uniform data sheets and

23:02.393 --> 23:04.449
unified field procedures to identify

23:04.449 --> 23:06.504
and delineate the O . H . W . M . Of

23:06.504 --> 23:06.040
rivers and streams located throughout

23:06.040 --> 23:08.640
the nation during this period that the

23:08.650 --> 23:10.872
O . H . W . Emanuel is still an interim

23:10.872 --> 23:13.300
draft O . H . W . M , identification

23:13.310 --> 23:15.670
and delineation for official uses .

23:15.670 --> 23:18.170
Regulatory purposes should continue in

23:18.170 --> 23:20.337
accordance with the applicable O . H .

23:20.337 --> 23:22.226
W . M . Definition in the federal

23:22.226 --> 23:24.392
regulations regulatory guidance letter

23:24.392 --> 23:27.260
0505 and any applicable uses district

23:27.260 --> 23:30.200
policies and procedures . However , the

23:30.200 --> 23:32.422
public and practitioners are encouraged

23:32.422 --> 23:34.533
to test and provide comments on their

23:34.533 --> 23:36.478
experience using the interim draft

23:36.478 --> 23:38.650
National or H . W . Emmanuel . The

23:38.650 --> 23:40.761
comments and feedback that we receive

23:40.761 --> 23:42.928
will be utilized to further refine the

23:42.928 --> 23:44.594
National Manual for clarity ,

23:44.594 --> 23:46.650
consistency and technical accuracy .

23:46.650 --> 23:48.872
You can find all the material including

23:48.872 --> 23:50.872
a link to the National Manual , The

23:50.872 --> 23:52.594
data sheet field procedure and

23:52.594 --> 23:54.650
supporting material at the O H . W .

23:54.650 --> 23:56.983
Website , which is the link shown below .

23:56.983 --> 23:58.650
Thank you very much for your time today