WEBVTT 00:01.950 --> 00:04.650 Hello . Welcome to an introduction to 00:04.650 --> 00:06.706 the ordinary high watermark National 00:06.706 --> 00:09.500 Manual . My name is dr Gabrielle David . 00:09.510 --> 00:11.760 I'm a researcher from the U . S . Army 00:11.770 --> 00:13.826 Engineering research and development 00:13.826 --> 00:15.770 center , cold regions research and 00:15.770 --> 00:17.714 engineering laboratory . Today I'm 00:17.714 --> 00:19.881 going to talk to you about the release 00:19.881 --> 00:19.850 of the interim draft for the National O . 00:19.850 --> 00:21.906 H . W . M . Field delineation manual 00:21.906 --> 00:24.072 for rivers and streams . I'll give you 00:24.072 --> 00:26.128 an introduction to the ordinary high 00:26.128 --> 00:28.350 watermark and provide background on the 00:28.350 --> 00:30.350 information you can find in the new 00:30.350 --> 00:30.170 National Manual . 00:35.210 --> 00:37.377 The National Manual was released as an 00:37.377 --> 00:39.950 interim version on November 30 , 2020 00:39.950 --> 00:42.780 to the US Army Corps of Engineers and 00:42.780 --> 00:44.780 Environmental Protection Agency are 00:44.780 --> 00:47.113 requesting feedback from uses districts , 00:47.113 --> 00:49.169 practitioners and the public through 00:49.169 --> 00:51.002 December 1 , 2023 . The National 00:51.002 --> 00:53.224 Technical Committee for O . H . W . M . 00:53.224 --> 00:55.447 A group composed of E . P . A Army corp 00:55.447 --> 00:57.870 regulators . Ergic researchers and 00:57.870 --> 01:00.400 academics plan to incorporate feedback 01:00.400 --> 01:02.511 into the final version so that we can 01:02.511 --> 01:04.511 make sure that this is a document , 01:04.511 --> 01:06.678 field procedure and data sheet That is 01:06.678 --> 01:06.420 helpful as possible for the 01:06.420 --> 01:08.031 practitioners in the field . 01:14.280 --> 01:16.502 The National Manual divides the country 01:16.502 --> 01:18.336 into eight regions including the 01:18.336 --> 01:20.669 Northwest , southwest Northern prairies , 01:20.669 --> 01:22.447 southern prairies , northeast , 01:22.447 --> 01:24.613 Southeast Alaska and Hawaii case study 01:24.613 --> 01:26.780 data were collected from each of these 01:26.780 --> 01:28.724 regions to include in the National 01:28.724 --> 01:28.710 Manual . The stars on the map show the 01:28.710 --> 01:30.488 locations of the case studies . 01:36.690 --> 01:38.470 So what does the ordinary high 01:38.470 --> 01:41.740 watermark mean ? The regulatory 01:41.740 --> 01:43.684 definition states that line on the 01:43.684 --> 01:45.796 shore established by the fluctuations 01:45.796 --> 01:47.740 of water and indicated by physical 01:47.740 --> 01:49.962 characteristics such as a clear natural 01:49.962 --> 01:52.073 line impressed on the bank , shelving 01:52.073 --> 01:53.907 changes in the character of soil 01:53.907 --> 01:56.129 destruction of terrestrial vegetation . 01:56.129 --> 01:58.184 The presence of litter and debris or 01:58.184 --> 01:58.110 other appropriate means that consider 01:58.110 --> 02:00.277 the characteristics of the surrounding 02:00.277 --> 02:04.160 areas Along with the definition of 02:04.170 --> 02:06.226 ordinary high watermark found in the 02:06.226 --> 02:07.948 Clean Water Act . We also have 02:07.948 --> 02:10.170 additional guidance from the regulatory 02:10.170 --> 02:12.170 guidance letter 0505 . The guidance 02:12.170 --> 02:14.281 letter describes a few other physical 02:14.281 --> 02:16.337 characteristics such as vegetation , 02:16.337 --> 02:18.448 matted down , bent or absent sediment 02:18.448 --> 02:18.190 sorting , leaf litter , disturbed or 02:18.190 --> 02:20.200 washed away , scour deposition , 02:20.210 --> 02:22.321 multiple observed flow events , water 02:22.321 --> 02:24.270 staining staining , changing plant 02:24.270 --> 02:26.381 community . These characteristics can 02:26.381 --> 02:28.492 all be important to identify but what 02:28.492 --> 02:30.659 do these physical characters that look 02:30.659 --> 02:32.881 like in different stream systems or how 02:32.881 --> 02:35.048 and when are they related to ? O . H . 02:35.048 --> 02:37.214 W . M . Is not described any further . 02:38.020 --> 02:40.187 Therefore , National Manual was needed 02:40.187 --> 02:42.409 to provide more information about these 02:42.409 --> 02:44.187 physical characteristics in the 02:44.187 --> 02:44.170 relationship to the ordinary high 02:44.170 --> 02:46.281 watermark , streams and rivers around 02:46.281 --> 02:48.448 the US come in all sorts of shapes and 02:48.448 --> 02:50.392 sizes , depending on the climate , 02:50.392 --> 02:52.670 geology and topography of the location . 02:52.670 --> 02:54.837 Therefore the physical characteristics 02:54.837 --> 02:56.837 that are indicators of the ordinary 02:56.837 --> 02:59.003 high watermark can look very different 02:59.003 --> 02:58.750 in these different environments . And 02:58.750 --> 03:00.806 National Manual is needed to provide 03:00.806 --> 03:02.972 more information on how to investigate 03:02.972 --> 03:04.861 sites for the H . W . M . And the 03:04.861 --> 03:07.083 differences in physical characteristics 03:07.083 --> 03:09.200 in these different environments . The 03:09.210 --> 03:11.432 overarching goal of the National Manual 03:11.432 --> 03:13.377 is to provide tools and supporting 03:13.377 --> 03:15.377 documentation to perform accurate , 03:15.377 --> 03:17.599 consistent and scientifically based O . 03:17.599 --> 03:19.599 H W . M delineations . I'm going to 03:19.599 --> 03:21.543 outline five goals in the National 03:21.543 --> 03:23.710 Manual and discuss how we address each 03:23.710 --> 03:25.877 of these within the manual . Therefore 03:25.877 --> 03:28.099 the goals of the National manual are to 03:28.099 --> 03:30.266 first provide consistent science based 03:30.266 --> 03:32.266 definitions of O H W M indicators . 03:32.266 --> 03:34.432 Second outline a clear decision making 03:34.432 --> 03:36.488 process using the weight of evidence 03:36.488 --> 03:38.710 approach , which I will talk about in a 03:38.710 --> 03:40.877 little bit . Third provide a forum for 03:40.877 --> 03:42.654 rapid and consistent field data 03:42.654 --> 03:44.877 collection . Fourth described landscape 03:44.877 --> 03:47.099 scales , considerations for O H W . M . 03:47.099 --> 03:49.180 Interpretation and five provide 03:49.180 --> 03:51.347 examples of case studies for difficult 03:51.347 --> 03:53.590 O H W . M delineations . The next set 03:53.590 --> 03:55.812 of sides go over each of these goals in 03:55.812 --> 03:59.800 detail . The first goal 03:59.800 --> 04:02.022 is to provide science based definitions 04:02.022 --> 04:04.690 of O H W . M indicators to do this . 04:04.700 --> 04:06.533 It's important to understand the 04:06.533 --> 04:08.589 hydrology of a stream system so that 04:08.589 --> 04:10.700 practitioners can go out and identify 04:10.700 --> 04:12.756 which indicators are related to high 04:12.756 --> 04:14.867 flows versus low flows . The National 04:14.867 --> 04:17.089 Manual discusses in detail the types of 04:17.089 --> 04:19.144 flows found in a stream to the right 04:19.144 --> 04:21.256 here is an example of a survey stream 04:21.256 --> 04:23.422 cross section . I'm gonna show you how 04:23.422 --> 04:25.478 flows can be over land and help with 04:25.478 --> 04:27.589 understanding which part of the cross 04:27.589 --> 04:29.589 section is likely to have O H W . M 04:29.589 --> 04:31.700 indicators . This cross section , for 04:31.700 --> 04:33.960 instance shows low or base flow up to 04:33.960 --> 04:36.440 this elevation , that elevation is the 04:36.440 --> 04:39.830 mean annual flow boundary above that is 04:39.840 --> 04:43.010 uh some moderate flows and then you 04:43.010 --> 04:45.530 start to get into the high flows . Now 04:45.530 --> 04:47.530 we're looking for the ordinary high 04:47.530 --> 04:49.760 watermark . So you would expect to find 04:49.760 --> 04:51.871 that in the part of the cross section 04:51.871 --> 04:55.610 that's inundated by high flows uh 04:55.620 --> 04:58.420 above there you have extreme flows 04:58.430 --> 05:00.400 which can continue to rise up and 05:00.400 --> 05:03.450 spread out over the hill slope or flood 05:03.450 --> 05:06.340 plain , uh depending on how big a flow 05:06.340 --> 05:08.507 it is , an extreme flows or flows that 05:08.507 --> 05:10.680 really substantially alter the cross 05:10.680 --> 05:12.736 section and the equilibrium state of 05:12.736 --> 05:15.030 the channel methods for developing 05:15.030 --> 05:16.697 these cross sections and flow 05:16.697 --> 05:18.863 visualizations at a site are described 05:18.863 --> 05:20.752 in detail in the manual and in an 05:20.752 --> 05:22.808 accompanying report , the hydrologic 05:22.808 --> 05:25.086 analysis of field delineated O H W . M . 05:25.086 --> 05:26.974 For rivers and streams . The flow 05:26.974 --> 05:28.974 visualizations are provided to help 05:28.974 --> 05:31.141 regulators the public understand again 05:31.141 --> 05:33.197 where you're likely to find low flow 05:33.197 --> 05:35.252 indicators versus where you would be 05:35.252 --> 05:37.080 finding high flow indicators . 05:39.940 --> 05:41.829 To better understand how physical 05:41.829 --> 05:44.080 indicators of flow form . It is helpful 05:44.080 --> 05:45.790 to have a better scientific 05:45.790 --> 05:48.340 understanding of streams . The O H W . 05:48.340 --> 05:50.507 M . Is a regulatory boundary , but the 05:50.507 --> 05:52.729 definition has a lot of similarities to 05:52.729 --> 05:54.896 other terms . Have been identified and 05:54.896 --> 05:57.007 defined in scientific literature such 05:57.007 --> 05:58.896 as bank fel . The National manual 05:58.896 --> 06:01.062 provides more detail on the definition 06:01.062 --> 06:03.284 of bank full and active channel and how 06:03.284 --> 06:05.451 and when these definitions can overlap 06:05.451 --> 06:09.070 with the H W . M . Before 06:09.080 --> 06:10.747 moving on . It's important to 06:10.747 --> 06:13.710 understand how the concept of active 06:13.710 --> 06:15.960 channel painful and O H . W . M . Are 06:15.960 --> 06:18.490 defined . So first , what is meant by 06:18.490 --> 06:20.750 active channel . This is a concept that 06:20.750 --> 06:23.870 is used widely but inconsistently . Uh 06:23.880 --> 06:25.991 Generally the phrase has been used to 06:25.991 --> 06:28.102 denote the unvetted stated portion of 06:28.102 --> 06:30.269 the channel or describe the section of 06:30.269 --> 06:32.547 channel below which bank slopes deeply . 06:32.547 --> 06:34.769 These two interpretations can result in 06:34.769 --> 06:36.936 very different portions of the channel 06:36.936 --> 06:39.158 being identified as the actor channel . 06:39.158 --> 06:41.269 Therefore , we outlined three primary 06:41.269 --> 06:43.630 criteria uh to distinguish the actor 06:43.630 --> 06:46.690 channel in the national manual , uh 06:46.700 --> 06:48.922 generally having to do with the portion 06:48.922 --> 06:50.756 of the valley bottom that has uh 06:50.756 --> 06:52.978 erosion and additional features created 06:52.978 --> 06:55.560 by ongoing river processes . Uh The 06:55.570 --> 06:57.737 upper elevation limit , which water is 06:57.737 --> 06:59.626 contained within a channel or the 06:59.626 --> 07:01.848 portion of channel without mature woody 07:01.848 --> 07:04.014 vegetation . Uh The first criteria can 07:04.014 --> 07:06.181 be very useful when looking at braided 07:06.181 --> 07:08.348 and multi thread systems where there's 07:08.348 --> 07:10.459 a lot of uh channel bars and a lot of 07:10.459 --> 07:12.570 secondary channels . So you're really 07:12.570 --> 07:14.681 looking at that portion of the valley 07:14.681 --> 07:16.737 that's being reworked by those river 07:16.737 --> 07:19.520 processes . The second criteria can be 07:19.520 --> 07:21.520 helpful when identifying the top of 07:21.520 --> 07:23.576 bank as an active channel but can be 07:23.576 --> 07:25.687 problematic and for instance , deeply 07:25.687 --> 07:27.631 incised systems where you wouldn't 07:27.631 --> 07:29.742 identify the top of that embankment . 07:29.742 --> 07:31.853 For instance , in this picture as the 07:31.853 --> 07:34.076 active channel . The third criteria can 07:34.076 --> 07:36.590 be useful uh in certain regions of the 07:36.590 --> 07:39.090 country , but in other climatic regions 07:39.100 --> 07:42.090 there's such as the southeast , there 07:42.090 --> 07:44.034 are woody species that grow in the 07:44.034 --> 07:45.812 stream bed . And so it's really 07:45.812 --> 07:47.910 important to put this channel in the 07:47.910 --> 07:50.620 landscape context of the region . 07:50.630 --> 07:53.480 Thinking about land use and vegetation 07:53.480 --> 07:56.760 and the climate uh when trying to 07:56.760 --> 08:00.040 identify what you mean by active 08:00.040 --> 08:03.910 channel . Here are 08:03.910 --> 08:05.854 three schematics showing different 08:05.854 --> 08:07.854 channel types to try to demonstrate 08:07.854 --> 08:10.630 where O . H . W . An active channel can 08:10.640 --> 08:13.050 overlap and where they may not 08:13.050 --> 08:15.840 necessarily overlap . And these are 08:15.840 --> 08:19.340 very simplified examples . So uh it may , 08:19.340 --> 08:21.173 there may be cases that in these 08:21.173 --> 08:23.229 channel types you may not always get 08:23.229 --> 08:25.173 overlap between where you identify 08:25.173 --> 08:27.530 Active channel and O H . W . M . But in 08:27.530 --> 08:30.630 this , in these examples uh in the 08:30.630 --> 08:33.610 braided anastomosis system , the H . W . 08:33.610 --> 08:35.832 And Active Channel would very likely be 08:35.832 --> 08:38.170 in the same location . Whereas in the 08:38.170 --> 08:40.380 stream wetland complex , there's a low 08:40.380 --> 08:42.870 flow channel that would most likely be 08:42.870 --> 08:45.290 identified as the active channel , but 08:45.290 --> 08:47.670 the H . W . M . The high water marks 08:47.670 --> 08:51.070 would be above that low flow channel 08:51.070 --> 08:51.720 system . 08:55.470 --> 08:57.980 There are very clear connections on how 08:57.980 --> 09:00.036 being full has been defined over the 09:00.036 --> 09:02.369 years . And the definition of O . H . W . 09:02.369 --> 09:04.536 M . The scientific literature contains 09:04.536 --> 09:06.480 a lot of similar wording , such as 09:06.480 --> 09:08.591 natural line and pressed on the banks 09:08.591 --> 09:10.758 transitions in soil and vegetation and 09:10.758 --> 09:12.536 presence of litter and debris . 09:18.160 --> 09:20.382 Therefore the indicators of O . H . W . 09:20.382 --> 09:21.827 M . Are similar to stream 09:21.827 --> 09:23.938 characteristics used to identify bank 09:23.938 --> 09:26.104 full in the National manual , we broke 09:26.104 --> 09:28.271 up these physical characteristics into 09:28.271 --> 09:30.104 four categories of geum or thick 09:30.104 --> 09:32.140 vegetation , sediment and ancillary 09:32.150 --> 09:34.500 indicators here we are just showing 09:34.500 --> 09:36.880 some examples of what types of physical 09:36.890 --> 09:39.112 characteristics can be found under each 09:39.112 --> 09:41.510 categories , such as break in slope , 09:41.520 --> 09:43.550 under geum or fick , lower limit of 09:43.550 --> 09:45.383 mature . What do you , perennial 09:45.383 --> 09:47.606 vegetation under vegetation , change in 09:47.606 --> 09:49.606 sediment texture under soil , under 09:49.606 --> 09:52.430 sediment or racking presence of organic 09:52.430 --> 09:54.610 litter or large . Would deposition 09:54.610 --> 09:55.570 under ancillary 09:59.170 --> 10:01.003 key points to remember about the 10:01.003 --> 10:03.320 science of O H . W . M . R . First that 10:03.320 --> 10:05.542 river and stream morphology czar shaped 10:05.542 --> 10:07.542 by relatively infrequent flows that 10:07.542 --> 10:09.764 typically occur on the order of several 10:09.764 --> 10:11.764 times per year to several times per 10:11.764 --> 10:14.270 decade . Therefore the H . W . M . Is 10:14.870 --> 10:17.510 shaped and maintained by flows that are 10:17.510 --> 10:20.220 well above mean annual flow but are not 10:20.220 --> 10:22.540 extreme . These are flows that maintain 10:22.540 --> 10:24.873 but do not substantially alter channels , 10:24.873 --> 10:28.060 geometry or location . The relationship 10:28.070 --> 10:29.792 between stream flow and stream 10:29.792 --> 10:31.959 characteristics are highly variable in 10:31.959 --> 10:35.170 space and time . No single recurrence 10:35.170 --> 10:37.281 and roll hydrologic statistic has the 10:37.281 --> 10:39.281 same geographic significance in all 10:39.281 --> 10:41.440 systems . So the H . W . M . Is not 10:41.440 --> 10:43.218 defined by specific stream flow 10:43.218 --> 10:45.384 recurrence interval such as a two year 10:45.384 --> 10:47.551 flood or fire five year flood , but it 10:47.551 --> 10:49.496 can be hydra logically constrained 10:49.496 --> 10:51.718 within a general range of recurrence in 10:51.718 --> 10:54.270 a role similar to bank , full flows and 10:54.270 --> 10:56.492 bank , full stage and the actual active 10:56.492 --> 10:58.159 channel limits our scientific 10:58.159 --> 11:00.270 counterparts . The regulatory concept 11:00.270 --> 11:01.270 of O H . W . M . 11:04.920 --> 11:06.976 Therefore O H . W . M . Delineations 11:06.976 --> 11:09.660 should utilize robust robust indicators 11:09.670 --> 11:11.550 of recurring high flows . 11:20.740 --> 11:22.740 The second goal of the manual is to 11:22.740 --> 11:24.962 outline a clear decision making process 11:24.962 --> 11:27.240 Using the weight of evidence procedure . 11:27.240 --> 11:29.351 The weight of evidence procedure is a 11:29.351 --> 11:31.462 logical process that provides a clear 11:31.462 --> 11:33.573 methodology for assembling evidence , 11:33.573 --> 11:35.890 evaluating awaiting the evidence and 11:35.890 --> 11:38.112 integrating different lines of evidence 11:38.112 --> 11:40.223 to come to a scientifically supported 11:40.223 --> 11:42.390 conclusion . The method provides a way 11:42.390 --> 11:44.223 to determine the significance of 11:44.223 --> 11:45.779 observations and to combine 11:45.779 --> 11:47.900 observations to arrive at this 11:47.900 --> 11:50.210 conclusion . Many may find that they 11:50.220 --> 11:52.331 already followed this logical process 11:52.350 --> 11:54.461 but just didn't have it outlined in a 11:54.461 --> 11:56.910 clear step by step way to follow this 11:56.910 --> 11:58.930 methodology . First , you assemble 11:58.930 --> 12:01.410 evidence . Many of the indicators that 12:01.410 --> 12:03.521 are listed as evidence of O H W . M . 12:03.521 --> 12:05.577 Are simply characteristics of stream 12:05.577 --> 12:07.688 flow and depending on hydrologic land 12:07.688 --> 12:09.854 use and geologic context of the system 12:09.854 --> 12:11.966 may be related to low flow high floor 12:11.966 --> 12:14.077 extreme flows . Therefore , the first 12:14.077 --> 12:15.966 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 12:20.243 --> 12:22.466 fick vegetation and sediment indicators 12:22.466 --> 12:24.660 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 12:29.003 --> 12:31.170 each line of evidence . The flow shown 12:31.170 --> 12:33.114 in the photograph and on the cross 12:33.114 --> 12:35.170 section is a low flow which is known 12:35.170 --> 12:36.948 from the USgs stream gauge data 12:36.948 --> 12:39.059 upstream . Therefore , the indicators 12:39.059 --> 12:41.070 near the low flow elevation are not 12:41.080 --> 12:43.320 relevant lines of evidence . These are 12:43.330 --> 12:45.460 obviously not high flow indicators . 12:46.060 --> 12:48.227 The third step is to weigh the body of 12:48.227 --> 12:50.550 evidence . This is logically combining 12:50.550 --> 12:52.772 where high flow indicators occur up and 12:52.772 --> 12:54.772 downstream and determining the most 12:54.772 --> 12:56.772 likely elevation of the H . W . M . 12:56.772 --> 12:58.960 From the combination of indicators 13:01.720 --> 13:04.050 to better understand how to weigh the 13:04.050 --> 13:06.050 body of evidence . So combining the 13:06.050 --> 13:08.328 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 13:21.250 --> 13:23.472 left is the site at low flow and on the 13:23.472 --> 13:25.583 right is the site with a hypothetical 13:25.583 --> 13:28.360 hypothetical ordinary high water level 13:28.380 --> 13:31.090 connecting the flow indicators up and 13:31.090 --> 13:34.210 downstream . So here the cut bank at 13:34.220 --> 13:37.220 the top of the figure is connected with 13:37.220 --> 13:39.490 the at the same elevation of the 13:39.490 --> 13:41.760 sandbar and where sand and claire 13:41.760 --> 13:44.030 getting mixed on the cut bank at the 13:44.030 --> 13:46.470 bottom of the figure , ah This also 13:46.470 --> 13:48.830 inundates completely the gravel bar on 13:48.830 --> 13:50.719 the opposite side of the stream . 13:56.650 --> 13:59.090 Therefore , the top of the bank at the 13:59.100 --> 14:00.933 top of that cut bank , the upper 14:00.933 --> 14:03.156 elevation the sandbar and transition to 14:03.156 --> 14:05.267 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