Reading RiverscapesMapping Valley Bottoms

LTPBR WORKSHOP

Purpose

•Get your eye trained for reading riverscapes

•Build your intuition about processes• Specifically, Wood

Accumulation & Beaver Dam Activity broken into component pieces:

• Hydrologic• Hydraulic• Geomorphic• Ecologic

i.e. Crash course in fluvial geomorphology

Recommend Fryirs & Brierley (2013)DOI: 10.1002/9781118305454

PHASE 1 with Low-Tech

Figure 3.3 (p. 91) from Bennett et al. (2019) – Chapter 3 LTPBR Manual

DOI: 10.13140/RG.2.2.15815.75680

PHASE 1 with Low-Tech

Figure 3.3 (p. 91) from Bennett et al. (2019) – Chapter 3 LTPBR Manual

DOI: 10.13140/RG.2.2.15815.75680

RECALL, Streams need space (i.e. their valley bottoms)

From Figure 2.1 (p. 60) Wheaton et al. (2019) Chapter 2 of LTPBR Manual

DOI: 10.13140/RG.2.2.19590.63049/1

What part of valley bottom is available for low-tech restoration?

Where are we talking about?

Remember This?From: Cluer & Throne (2013) DOI: 10.1002/rra.2631

How much of valley bottom?

Figure 3.7 from Bennett et al. (2019) – Chapter 3 LTPBR Manual

DOI: 10.13140/RG.2.2.15815.75680

We care about Mesic Habitat – i.e. RiparianCross Sectional Valley View

• Riparian vegetation associations with different surfaces

• Floodplain = Valley Bottom = MAXIMUM Probable Riparian Extent

• Terraces = Former Floodplains

• Uplands = NON-Riparian

The lateral and vertical dimensions…

From: USFS (2004) Riparian Restoration(SDTDC 04231 1201)

Riparian Dimensions & Connectivity

• Vertical cross section determines water availability

• Longitudinal patterns control fluxes of water, sediment, nutrients and seeds (sources, transfer vs. sinks) From: USFS (2004) Riparian Restoration

(SDTDC 04231 1201)

• Lateral extent determines potential width of riparian area

What is a Valley?

From Glossary in Wheton et al. (2019, p 20) – LTPBR Manual. DOI: 10.13140/RG.2.2.19590.63049/2

Valley Bottom vs. Valley?

What are the building blocks of: • A Valley?

vs.• A Valley Bottom?

From: Wheaton et al. (2015) – Geomorphology; DOI: 10.1016/j.geomorph.2015.07.010

Valley Margins In Different Settings

• Interesting thing is identifying where different margins overlap

• Fundamental control on channel’s capacity to adjust

• Differentiates reach types

• Sets up planform steering of flows

From: Wheaton et al. (2015) – Geomorphology; DOI: 10.1016/j.geomorph.2015.07.010

From: Fryirs et al. (2015) – ESPL;DOI: 10.1002/esp.3893

Reading your riverscape… to look for opportunities

From page 9 of Pocket Guide; Wheaton et al. (2019) DOI: 10.13140/RG.2.2.28222.13123/1

Where are their mesic/riparian restoration opportunities?

From page 10 of Pocket Guide; Wheaton et al. (2019) DOI: 10.13140/RG.2.2.28222.13123/1

Contrasting Valley Settings Define Reach Breaks

From pages 9-10 of Pocket Guide; Wheaton et al. (2019) DOI: 10.13140/RG.2.2.28222.13123/1

← Which way is river flowing? →

Exercise – Reading Valley SettingSouth Fork Asotin CreekRiver Mile 1.5 to 2.2

0 750 1000 ft250 500

1. Map Channel(s)2. Map Fan(s) and/or Terrace(s)3. Map Active Confining

Margin(s)4. Estimate % Confinement

ContextSouth Fork Asotin CreekRiver Mile 1.5 to 2.2

0 750 1000 ft250 500

NHD Stream Network –Perennial Line (1:24,000)

Trace the Actual ChannelSouth Fork Asotin CreekRiver Mile 1.5 to 2.2

0 750 1000 ft250 500

Map the Fans

Anthropogenically Disconnected river left Fans

Coupled river left fans

South Fork Asotin CreekRiver Mile 1.5 to 2.2

0 750 1000 ft250 500

Map the Confining Margins

Hillslope/Bedrock(HS/BR) Fan

Fan

FanFan

Anthropogenic - Road

South Fork Asotin CreekRiver Mile 1.5 to 2.2

0 750 1000 ft250 500

Natural Capacity For Adjustment

• Plausible limits on what adjustments are possible

• Geomorphic context matters• Confinement• Sediment Supply• Flow Regime• Vegetation• Land use• History

From Brierley & Fryirs (2005)

Valley Bottom (Riparian) Delineation

Sets maximum lateral extent for potential riparian & flooding

From http://rcat.riverscapes.xyz

Key Question(s):• What is in play for

freedom space?• What is the maximum

probable extent of riparian vegetation?

From: Gilbert et al. (2016) DOI: 10.1016/j.cageo.2016.07.014

V-BET: Valley Bottom Extraction Tool• From topography (e.g. USGS 10

m NED or LiDAR) & V-BET

From: Gilbert et al. (2016) – Computers & Geosciences ; DOI: 10.1016/j.cageo.2016.07.014http://rcat.riverscapes.xyz

VBET with Higher Resolution Data?

• More precise answer (better resolved)

• Coarser data may be accurate enough in many cases

From: Gilbert et al. (2016) DOI: 10.1016/j.cageo.2016.07.014

Province-wide or Watershed Wide: VALLEY BOTTOMS

• Tool can run @ broad spatial scales from DEM (e.g. here for Utah over 25,000 km of riverscape in a region ~ 220,000 km2 ; by comparison Upper yellow River is about 140,00 to 178,000 km2)

Making Investment

https://restoration-usu.github.io/Ecohydraulics/Modules/NetworkTools.html#network-scale-assessments

Want to learn more?

Map Confinement – Understand Valley Setting

From: Fryirs et al. (2015) – ESPL;DOI: 10.1002/esp.3893

From: O’Brien et al. (2019) – ESPL;DOI: 10.1002/esp.4615

Check out: Confinement Tool in GNAT: http://gnat.riverscapes.xyz/

Inputs: VB + Channel(s) Position

Mapping margin types helps identify connectivity to local sediment supplies

From: O’Brien et al. (2019) : DOI: 10.13140/RG.2.2.28838.57924/1

Stacked Profile Plots

Network models of Geomorphic Attributes

Give us reach types (River Styles) and condition

Check out: Confinement Tool in GNAT: http://gnat.riverscapes.xyz/ &Network Profiler Tool: https://riverscapes.github.io/NetworkProfiler/

From: O’Brien et al. (2019) : DOI: 10.13140/RG.2.2.28838.57924/1

Reading Riverscapes – On your own time…

http://lowtechpbr.restoration.usu.edu/resources/Topics/03_Planning/sturcturalForcing

To help you experience a little of what you would with an in-person workshop• We take you out in the field

virtually with the help of UAVs, GoPro, some maps, and some narration by Joe

• Includes: