140L5725Q0003_-_Attachment_006_-_CO-NRCS_Range_Technical_Note_40_Gunnison_Zeedyk-Structures_5-18.pdf

TECHNICAL NOTES

U.S. DEPARTMENT OF AGRICULTURE STATE OF COLORADO NATURAL RESOURCES CONSERVATION SERVICE

Range Technical Note No. 40 May 2018

Hand-Built Structures for Restoring Degraded Meadows in Sagebrush Rangelands

Examples and lessons learned from the Upper Gunnison River Basin, Colorado

Zeedyk rock structures installed to restore incised channel. Photo by: Nathan Seward ii

FOTG, Section I NRCS, CO

Technical Notes, Range May 2018

Purpose: Gully erosion and channel incision are widespread problems reducing the function and resilience of wet meadows and riparian areas. The loss of natural water storage capacity in these systems is of concern in low-precipitation areas where wet-mesic areas represent a small fraction of the landscape but are disproportionately important to wildlife and livestock. This technical note provides conservation practitioners with information on simple yet effective “Zeedyk” restoration techniques. The emphasis here is on structures that can be built by hand to address shallow headcuts or small incised channels (< 4 ft deep) impacting meadows and low-to-moderate gradient (< 3% slope) intermittent/ephemeral drainages in sagebrush rangelands. The note provides examples and lessons learned from partners in the Gunnison

Climate Working Group who have been implementing a landscape-scale project using these techniques in the Upper Gunnison River Basin, Colorado. The note provides information and references to help practitioners identify opportunities, prioritize treatments, and design projects in similar watersheds across the West.

Authors

Jeremy Maestas, Ecologist, USDA-NRCS, West National Technology Support Center, Portland, OR

Shawn Conner, Restoration Ecologist, BIO-Logic, Inc., Montrose, CO

Bill Zeedyk, Zeedyk Ecological Consulting, LLC, Sapello, NM

Betsy Neely, Climate Change Program Manager, The Nature Conservancy, Boulder, CO

Renee Rondeau, Ecologist, Colorado Natural Heritage Program, Ft. Collins, CO

Nathan Seward, Terrestrial Biologist, Colorado Parks and Wildlife, Gunnison, CO

Teresa Chapman, GIS Manager, The Nature Conservancy, Boulder, CO

Liz With, Program Specialist, USDA-NRCS, Gunnison, CO

Rachel Murph, State Rangeland Management Specialist, USDA-NRCS, Denver, CO

Acknowledgements

We thank all the members of the Gunnison Climate Working Group Project Team, especially Jim

Cochran (Gunnison County), Matt Vasquez (Gunnison National Forest), Andrew Breibart (Bureau of

Land Management), Frank Kugel (Upper Gunnison River Water Conservancy District) and the private ranchers and landowners for making this project possible. We also thank the Quivira Coalition for their vision and sustained support for Bill Zeedyk’s innovative work. Finally, we thank Craig Sponholtz for providing permission to utilize his structure diagrams.

Suggested Citation

Maestas, J. D., S. Conner, B. Zeedyk, B. Neely, R. Rondeau, N. Seward, T. Chapman, L. With, and R.

Murph. 2018. Hand-built structures for restoring degraded meadows in sagebrush rangelands: Examples and lessons learned from the Upper Gunnison River Basin, Colorado. Range Technical Note No. 40.

USDA-NRCS, Denver, CO.

USDA is an equal opportunity provider, employer, and lender.

iii

Table of Contents

I. Introduction

Background

Gunnison Basin Wet Meadow and Riparian Restoration and Resilience-Building Project

II. Reading the landscape to recognize problems and opportunities

Basic geomorphic landforms

Channel incision, gully erosion, and headcuts

Vegetation indicators

Soils and sediment

III. Zeedyk approach for treating headcuts and gullies

Thinking like water

Critical role of vegetation

Healing principles

IV. Zeedyk structure types and key features

Headcut control techniques

Zuni Bowl

Rock Rundown

Rock Layback

Log and Fabric

Grade control techniques

One Rock Dam

Filter Dam

Flow dispersal techniques

Media Luna

Related techniques

V. Project planning

Goals and objectives

Prioritization

Site evaluation and inventory

Treatment design and placement

Consultation and permitting

VI. Pre-construction and installation

Laying out and staking structures iv

Estimating structure materials

Sourcing and delivering materials

Training field crews and contractors

Construction

VII. Monitoring and maintenance

Structure condition and performance monitoring

Outcome-based monitoring

Compliance monitoring

VIII. References

IX. Glossary of key terms

X. Appendices

Technical Notes, Range May 2018

I. Introduction

Background

Riparian areas and wet meadows occupy a small fraction of rangeland ecosystems, yet these mesic areas provide critical resources for many species and are especially crucial during periods of drought.

Functioning meadows and floodplains capture and hold water in the soil, slowly releasing it after runoff events, sustaining continued base flows, and maintaining higher water tables throughout the growing season. Holding water in the soil later into the summer season results in plant communities that are more productive than surrounding landscape, making them attractive for wildlife and livestock.

However, the hydrological and ecological function of many riparian and meadow areas have been degraded by gully erosion, channel incision, and lowered water tables. Causes are varied but often include current and past land uses, such as, improper grazing, soil compaction by livestock and wildlife trailing, roads, historic flooding events, and invasive plant species. Given the scale of the problem, restoration techniques that are relatively simple, cost-efficient, and effective are needed in the toolbox to allow more conservationists and landowners to engage in implementation.

This publication provides information on a suite of techniques for erosion control and restoration in semi-arid systems pioneered by Bill Zeedyk (Zeedyk Ecological Consulting, LLC), with support from the

Quivira Coalition (Zeedyk and Jansens 2009; Zeedyk and Clothier 2014; Zeedyk et al. 2014; Zeedyk

2015). Restoration techniques include installation of simple structures that kickstart regenerative hydrologic and ecological processes to reduce or reverse degradation over time. In general, structures are designed to slow and disperse water, dissipate energy, capture sediment, and increase soil moisture, thereby promoting mesic and wetland plant species expansion and channel recovery. Benefits of structures are varied but include improved wildlife habitat, water quality and quantity, soil health and carbon sequestration, forage for livestock, drought resilience, and overall watershed function.

While a variety of Zeedyk techniques have been developed for various situations, the focus of this note is on a subset of hand-built rock or wood structures that can be used to treat wet meadows and intermittent/ephemeral streams impacted by gully erosion in sagebrush rangelands. The emphasis is on addressing relatively shallow headcuts or small incised channels (< 4 ft deep) where recovery to desired floodplain or meadow surfaces can be achieved in a reasonable timeframe without heavy machinery and earth work.

Anytime conservationists are working in riparian and wet meadow systems, it is highly recommended that an interdisciplinary approach be taken (e.g., including hydrologists, ecologists, geomorphologists). Given the landscape position of these systems, many watershed-level geomorphic and hydrologic factors

Technical Notes, Range May 2018 influence their sensitivity to disturbance and inform restoration (Chambers et al. 2004). It is not within the scope of this publication to be a comprehensive planning guide or encompass watershed-scale considerations. Instead, the focus here is to help natural resource managers identify relatively low-risk opportunities for restoration and introduce a suite of potential treatment techniques.

Gunnison Basin Wet Meadow and Riparian Restoration and Resilience-Building Project

This note draws upon examples and lessons learned from the Gunnison Basin Wet Meadow and Riparian

Restoration and Resilience-Building Project, which is a watershed-scale effort that has installed and monitored over 1,000 Zeedyk structures across the Upper Gunnison River Basin, Colorado (Fig. 1; TNC

2017; TNC and GCWG 2017). The project is led by the Gunnison Climate Working Group Project Team

(GCWG)1 – a public-private partnership that has been working collaboratively since 2012 to restore wet meadows and enhance resilience to help wildlife and ranchers in the face of drought and a changing climate.

The Upper Gunnison River Basin is home to the federally threatened

Gunnison sage-grouse (Centrocercus minimus) where the loss of wet meadows for brood-rearing habitat has been a concern. Sage-grouse rely on mesic habitats, especially during the summer, to provide abundant food resources to feed growing chicks. These areas also provide important habitat for a host of other wildlife species, such as, deer, elk, migratory birds, and amphibians. Many wet meadows in the

Gunnison Basin have already been impacted by erosion and lowered water tables and are likely be further impacted (or stressed) by increasing drought and intense precipitation events associated with warming temperatures. To address

1GCWG Project Team Members: Gay Austin and Andrew Breibart (Bureau of Land Management-Gunnison Field Office), Teresa

Chapman and Betsy Neely (TNC), Jim Cochran (Gunnison County), Shawn Conner (BIO-Logic, Inc.), Jonathan Coop and Pat

Magee (Western State Colorado University), Tom Grant and Frank Kugel (Upper Gunnison River Water Conservancy District), Imtiaz Rangwala (Western Water Assessment), Renée Rondeau (Colorado Natural Heritage Program), Nathan Seward (Colorado

Parks and Wildlife), Theresa Childers (National Park Service), Brooke Vasquez (Gunnison Conservation District), Matt Vasquez

(US Forest Service), Liz With (Natural Resources Conservation Service), and Bill Zeedyk (Zeedyk Ecological Consulting).

Figure 1. Wet meadow and riparian restoration project area in the Upper

Gunnison River Basin, CO. Figure by: Teresa Chapman

Technical Notes, Range May 2018 these concerns, partners in the Basin have been working to improve hydrologic and ecological function of wet meadows and riparian areas to prepare for a changing future.

The Gunnison Basin Wet Meadow and Riparian Restoration and Resilience-Building Project serves as an important demonstration of simple and effective tools for increasing resilience of wet meadow and riparian habitats. Approaches applied in this project are transferable to other areas with similar goals and landscape conditions across the sagebrush steppe. For more information on this project, visit www.conservationgateway.org and search for Gunnison Basin.

II. Reading the landscape to recognize problems and opportunities

Landform, morphology, soils, and vegetation all provide important clues about the current function and potential of a site. Learning to read the landscape to recognize resource problems and restoration opportunities is both an art and science. Below are a few key features to pay attention to when walking a watershed that may help you identify situations where Zeedyk restoration techniques could be useful.

Basic geomorphic landforms

Identifying the basic landforms within a valley is helpful when planning in riparian and meadow systems

(Fig. 2; Wheaton et al. 2015). The margins of a valley can be described as the area between the bases of adjacent hillslopes, or uplands. The valley bottom is the area within a valley that includes the channel (if present) and active floodplain. The valley bottom margin may abut hillslopes or other features like terraces (former floodplains) and alluvial fans (fan-like sediment deposits usually at the mouth of an adjoining canyon). Larger wet meadow complexes are often located just upstream of alluvial fans or rock outcrops. Identifying the valley bottom is especially useful as it defines the maximum extent of riparian vegetation under current conditions.

Figure 2. Basic geomorphic and fluvial landforms in a valley (from Wheaton et al. 2015).

http://www.conservationgateway.org/

Technical Notes, Range May 2018

From a cross-sectional view of the channel, the bankfull elevation is the point at which water flows onto the floodplain (aka, ordinary high water or channel-forming flow). The relationship of bankfull elevation to channel depth is important as it affects water availability to support riparian vegetation.

Channel incision, gully erosion, and headcuts

Channel incision is the process of downcutting in a stream channel leading to a lowering of the channel bed elevation. An incised channel is one in which a stream has lost access to its floodplain. Meadow systems typically lack a discernable channel but can be impacted by incision through the process of gully erosion when surface flows become concentrated and downcut into meadow soils. The term “gully” is often used broadly to describe various types of incision.

Most visible channel incision and gullies occur and advance by way of headcuts (aka, nickpoints or gully-heads). Headcuts are identifiable points of active incision where there is an abrupt change in channel gradient, creating a waterfall and plunge-pool (Fig. 3). Water accelerates as it plunges off the headcut ledge, generating turbulence, scouring bed material to form a pool, and undercutting the drop-off by eroding soils. Vegetation that once held soils together is left dry, resulting in plant mortality that allows the headcut to advance upstream.

Once gullies are formed, groundwater sapping (seepage erosion) can further accelerate incision in meadows as well.

There are few things in nature that can stop a headcut from advancing once started. The rate at which headcuts migrate upstream depends heavily upon the soil textures and structure, vegetation, and water flow. Headcuts typically move upvalley in stages as bed erosion continues until an impermeable substrate, such as bedrock or tree roots, is reached and a new grade established.

Figure 3. Top: Headcut advancing in meadow. Bottom:

Plant roots on the headcut lip become exposed resulting in mortality. Photos by: Kyle Tackett

Being able to recognize headcuts in the field provides an opportunity to intervene to protect upstream riparian areas and meadows that have not yet been incised.

Technical Notes, Range May 2018

Once incision begins, most channels tend to undergo a sequence of changes that are fairly predictable (Fig. 4; Schumm et al. 1984).

When degraded, previously stable channels or meadows first downcut (stages I and II), then widen (stage III), then aggrade (stage IV), and ultimately stabilize at a new, lower elevation within the gully trench (stage V). While overly-simplistic, it is a helpful conceptual model for considering what stage of the evolution process your site might be in as it can inform the type of restoration approach used. Early intervention using the techniques described in this publication can help reverse incision by accelerating natural processes that more quickly restore floodplains, water table connectivity, and stable riparian and meadow systems.

Human nature is to tackle the most severe gullies on the landscape first. However, the cost of doing so can be very high in terms of the amount of effort needed to recover those sites, the potential risk of failure, and the foregone opportunity to prevent further degradation in less impacted areas. If given the choice, it is highly recommended that conservationists prioritize sites that are still in the early stages of channel evolution (stages II and III) where headcuts and gully trenches are relatively low. The degree of incision can also be estimated by the bank height ratio, or the ratio of the floodplain bank height to the bankfull channel height (Rosgen 1996). Areas with low bank height ratios offer a higher potential reward versus cost/risk.

Vegetation indicators

Vegetation can be indicative of hydrologic function of a site. Incision results in a lowering of the water table and capacity to store water in soils, which induces changes in riparian and meadow vegetation (Fig.

5). Prior to incision, functioning channels and meadows maintain high water tables across the valley bottom which create conditions that support wetland, mesic, and riparian plants (wetland indicator status:

obligate (OBL), facultative wet (FACW), facultative (FAC); see Lichvar et al. 2012). After incision, these species give way to dryland species, such as, sagebrush (wetland indicator labels: facultative upland

(FACU), upland (UPL). Most sagebrush species cannot tolerate saturated soils; sagebrush presence on a floodplain or meadow is an indicator of an altered hydrology. Even subtle shifts in vegetation, from mostly wetland obligate species (OBL) to mesic species (FACW) to riparian species (FAC), can indicate

Figure 4. Channel evolution model from Schumm et al. (1984).

Courtesy of W.B. Southerland.

Technical Notes, Range May 2018 a shift from wet to drier conditions resulting from a lower water table and potentially reduced hydrologic function.

Soils and sediment

Erosion is a natural process that results in relocation of soils when transported by water through sedimentation. It is neither good nor bad, but a process in watersheds. However, site degradation can occur when accelerated erosion results in sediment transport that exceeds replenishment rates.

Considering the sediment supply to your project site is helpful as sediment is also a resource that can assist in restoring incised channels. Detailed assessments of sediment supply can be done but simple indicators on degraded sites, such as bare sediment deposition on vegetated surfaces and point bars in channels, can be clues to the current amount and type of sediment. Sites with more sediment may allow faster recovery of incised channels.

Examining the channel bed and cutbanks within the incision trench also provides useful information.

Sediment in a valley floor (alluvium) is typically sorted by natural processes resulting in layering, or strata, in the soil profile. Larger, heavier soil particles like cobble and gravel mostly end up on the lower layers and finer particles like sand, silt, and clay are typically deposited in the upper layers. In terrace cutbanks, look for darker soils, rich in organic matter, and hydric soil indicators in the upper strata as evidence of a recently disconnected floodplain. Channel beds comprised of thick fine-grained particle layers may still be actively downcutting until the less mobile cobble/gravel layers are reached, or stabilization measures are implemented.

Figure 5. Panel A: Typical change in vegetation types with incision and lower water tables (adapted from Dickard et al.

2015). Panel B: Actual water table depths (means + S.E.) for typical meadow ecological types in the central Great Basin

(from Chambers et al. 2004).

Technical Notes, Range May 2018

Where the cobble/gravel layers intercept the channel, the stream is connected to the valley’s near-surface groundwater. Groundwater moves down valley through this cobble/gravel layer. When flows in this layer are in direct contact with fine-grained layers, it serves as a mechanism to sub-irrigate the valley through capillary action in the soil that wicks water up to plant roots. Conversely, channel incision can drain riparian areas and meadows by lowering the base flow and reducing capillary action. This presents an opportunity to enhance riparian and meadow vegetation by restoring sub-irrigation of the first terrace in an incised channel by raising the elevation of the riffles in order to put the water surface at base flow back in contact with the cobble/gravel layer and restore capillary flow to root zones (Zeedyk and Clothier

2014).

III. Zeedyk approach for treating headcuts and gullies

After reading the landscape to identify challenges and opportunities, the Zeedyk restoration approach requires practitioners to think about how water flows through the system and interacts with vegetation so it can be managed to support restoration goals.

Thinking like water

Four basic sources of streamflow include: 1) groundwater flow that provides base flow of the stream, 2) interflow from the soil moisture zone that augments base flow, 3) surface runoff from overland flow that contributes to streamflow during storms or snow melt, and 4) precipitation falling directly into channel

(Zeedyk and Clothier 2014).

Gullies are often initiated when dispersed overland flow converges to channelized concentrated flow, increasing the velocity of water and erosive potential. Once incision begins, seepage from groundwater and interflow can further exacerbate gullies. Incised channels have higher stream power (a function of water velocity, channel width and depth) as flow is forced to move through a smaller area with steeper gradient.

The energy of flowing water is dissipated primarily through roughness, erosion, and sediment transport. Roughness refers to the obstacles water encounters along its path and includes things that interrupt flow, like vegetation and rocks, and features that

Zeedyk techniques work with water and natural processes that dissipate energy to reverse degradation and accelerate recovery of incised channels.

Technical Notes, Range May 2018 create drag, like pools, riffles, and meanders.

Streambank erosion serves to widen channels and create floodplains and is another mechanism by which flowing water is slowed and energy dissipated. Flow containing sediment carries less energy than clear running water which tends to be more erosive. With this in mind, bank erosion and sediment become resources that can be harnessed and put to work building floodplains for enhanced roughness and channel recovery.

Critical role of vegetation

Promoting healthy riparian, meadow, and upland vegetation is essential to stabilizing incised channels and facilitating recovery. The critical role of plants is often underestimated, but is a key component of the Zeedyk restoration approach.

Above ground, plant stems provide roughness to redistribute flow patterns and facilitate deposition and soil building. Below ground, living plant roots feed the biological processes that help bind soil particles and provide stability. Healthy roots enhance the ‘sponge’ capacity of the soil by creating pore space that allows for better infiltration of overland flow and precipitation which affects how fast water moves through the system and into the channel.

Zeedyk structures are designed to work in concert with vegetation to stabilize and recover degraded sites (Fig. 6). For structures to be successful, land management practices in meadows and surrounding uplands must be compatible with the maintenance of healthy vegetation. Many practices can affect vegetation but a primary consideration

Figure 6. Extent of wetland vegetation before Zeedyk structures

(2012) and 2-4 years post-treatment (2014 and 2016). White polygons represents the area supporting predominantly wetland vegetation. Photos by: Claudia Strijek (2012) and Renee

Rondeau (2014, 2016)

Technical Notes, Range May 2018 in rangeland settings is grazing. Improper grazing and trailing by livestock and wildlife can reduce plant health and vigor. There are many strategies for managing grazing to be compatible with vegetation goals

(Swanson et al. 2015), including adjustments in timing of use or installation of drift fences to reduce trailing in valley bottoms. Practitioners should consider proper grazing management, and potentially other upland treatments (e.g., pinion-juniper removal), as integral components of the restoration plan.

Healing principles

Zeedyk techniques generally seek to slow and disperse water, dissipate energy, capture sediment, and increase soil moisture retention thereby promoting vegetation and channel recovery. The following are some principles to follow when treating headcuts and gullies from Zeedyk and Jansens (2009):

IV. Zeedyk structure types and key features

Here, we describe several types of hand-built Zeedyk structures that have been successfully applied at a large scale through the Gunnison Basin Wet Meadow and Riparian Restoration and Resilience-Building

Project (TNC and GCWG 2017). The project setting is a semi-arid sagebrush landscape within in the

Upper Gunnison River Basin, Colorado. The area receives 8-16 in of annual precipitation that falls predominantly as winter snow and summer monsoonal rain events that can create localized floods. Hand-built structures were constructed primarily on shallow headcuts and small incised channels of ephemeral/intermittent streams and meadows where the incision was not too deep (< 4 ft).

Zeedyk structures can be characterized by what they are primarily designed to achieve: 1) headcut control, 2) grade control, and 3) flow dispersal. Headcut control structures result in preservation of

Principles for Treating Gullies:

• Disperse surface flow, prevent concentration, increase infiltration and percolation.

• Reduce channel slope to reduce runoff velocities to reduce available energy.

• Widen channel bottom to lessen erosion force.

• Increase channel roughness.

• Retain soil moisture to improve environment for colonization and growth of plants.

Principles for Treating Headcuts:

• Lower the height of the falls in order to reduce the force of falling water.

• Widen the lip of the falls to disperse concentrated flow.

• Harden the base of the falls to protect substrates from erosion.

• Conserve soil moisture to enhance plant growth and root densities.

Technical Notes, Range May 2018 riparian and meadow areas upstream that will be degraded without intervention. Grade control and flow dispersal structures are intended for restoration of riparian and meadow areas with low-to-moderate gradients (< ~3% slope) that have already been degraded. This is an important distinction when articulating and monitoring intended project outcomes. Multiple types of structures are often installed together in a treatment complex and are designed to work in concert to achieve desired objectives within a reach. Treatment should begin at the top of the watershed and work down, which frequently requires coordination across land ownerships.

While Zeedyk structures may appear similar to traditional techniques, such as check dams and gully plugs, there are some subtle but important differences. Zeedyk structures are low-profile in the channel and meant to work with the system slowly over time to foster processes that lead to recovery (like floodplain development). They are not intended to impound water, capture as much sediment as possible, and walk away. To build Zeedyk structures properly, individual pieces of rock or wood must be carefully placed to ensure water flows over them in a specific manner that promotes stability and vegetation growth rather than serving as barriers to flow that often results in structures being end-cut or undermined. Zeedyk structures are relatively low-risk and cost-effective compared to traditional approaches, allowing more to be implemented in series which reduces the importance of any one structure. However, installation of these structures can be more labor intensive and often requires multiple interventions through time.

Highlighted below are various structure types with a brief description of what they are designed to do, where to locate them, and some key design features to pay attention to during construction. For additional details on these structures, refer to the following publications: Sponholtz and Anderson (2013) and

Zeedyk and Clothier (2014).

Headcut control techniques

Headcuts are critical erosional features to treat, as they migrate upstream and can lead to further channel incision, gully formation, dewatering and the potential loss of areas of wet and mesic meadows. Of the headcut control structure types listed below, deciding which to use is usually a function of the headcut size and type (Table 1). All have the purpose of stopping the advancement of a headcut, and stepping the water down into the channel to minimize the erosive power.

Table 1. Potential Zeedyk structures to treat various types of headcuts.

Technical Notes, Range May 2018

Zuni Bowl

The Zuni bowl is a rock-lined, step falls with plunge pools used to dissipate the energy of falling water and stabilize a headcut (Fig. 7, 8, 9). These structures stabilize the progression of a headcut by both stepping down the water in a way that minimizes the erosive and scour potential of falling water, and by protecting and maintaining moisture and vegetation at the pour-over. Hand-built Zuni bowls are typically applied to treat in-channel headcuts (1.5-3 ft tall). See Appendix A for construction specifications.

Some key features:

• The headcut pour-over is a critical location and the top rocks of the wall must match the existing elevation of this pour-over so that water freely flows over the structure (Fig. 7). Trim the headcut back to expose live roots as the maintenance of healthy vegetation at this spot is key to stopping the progression of the headcut.

• When building the back wall up the face of the headcut, offset the layers of rock for stability and lean them back to form a sloping wall around the headcut instead of trying to build a vertical wall.

• Armor the plunge pool with tightly-placed rock of sufficient size to avoid scouring.

• Construct a one rock dam (ORD, described below) downstream of the Zuni bowl to create another pool (Fig. 8, 9). Place the upstream edge of the ORD 4-6 times the height of the headcut away from the bottom of the Zuni bowl.

Figure 7. It is critical to ensure the top rocks of the Zuni bowl wall match the existing elevation of the headcut pour-over

(denoted by yellow arrow). This helps irrigate vegetation at the lip, allowing it to become the most vigorous instead of the weakest point subject to erosion. If rocks are too high, they divert water around structure, concentrate flow, and potentially cause new gullies. If rocks are too low, soils and roots are exposed and vegetation dies. Photo by: Nathan Seward

Figure 8. Zuni Bowl plan and cross-sectional views (Sponholtz and Anderson 2013; figure courtesy of C. Sponholtz).

Figure 9. Placing a one rock dam (ORD) just downstream of the Zuni bowl creates another pool (denoted by yellow arrow).

Where there used to be one drop with the headcut, there are now three to dissipate energy. Pooled water also irrigates the banks which strengthens vegetation and reduces erosion potential. Photo by: Shawn Conner

Technical Notes, Range May 2018

Rock Rundown

The rock rundown structure is used in low energy headcuts (< 1.5 ft tall) in small catchments and off-channel return sites to stabilize them and prevent upstream erosion (Fig. 10). Typically, the headcut is first laid back by shaping it to a stable angle (3:1 slope), and then the slope is armored with rock. In some small headcuts, shaping is not required. See Appendix B for construction specifications.

Figure 10. The center of a rock rundown should be the lowest so water runs down the middle and not around the structure.

Photo by: Nathan Seward

Some key features:

• Make sure the rocks at the pour-over lip are at the same elevation of the headcut so that water flows freely over it and trim the headcut back until live plant material and roots are exposed.

• The center of the rundown should be the lowest, so water runs down the middle and not around the structure.

• The tighter the rocks fit together the better to eliminate gaps between rocks as much as possible.

• Another version of the rock rundown is the “rock mulch” which can be utilized in areas outside or adjacent the main channel to armor or prevent trampling alongside in-channel structures (Fig. 11).

Rock Layback

The rock layback is used to treat long headcuts that are often in areas subject to shallow and well-dispersed, low velocity sheet flow events (Fig. 12). Laybacks are built by shaping the shallow headcut back to a slope which will accept a stacked rock wall for armor, and exposing live vegetation roots at the pour-over lip. See Appendix C for construction specifications.

Figure 11. Rock mulch can be used in off-channel areas to address minor headcuts and return flow sites. Photo by: Nathan

Seward

Figure 12. Rock laybacks can be used to treat long, shallow headcuts. Start with a row of large rocks as the footer, then build the stacked wall of rocks by leaning rocks into the slope for stability. Ensure the top rocks of the layback wall match the existing elevation of the headcut pour-over (denoted by yellow arrow). Photo by: Shawn Conner

Technical Notes, Range May 2018

Some key features:

• Create a footer for a splash apron to eliminate the scour pool. Begin with a row of large rocks as the base to build the stacked wall of rocks.

• Batter, or lean, rocks back into the slope for stability.

• The rock wall should be even with the lip of the headcut pour-over.

Log and Fabric

The log and fabric step falls is used in larger (up to 4 feet tall) in-channel headcuts and in areas where access to logs is more practical than rock (Fig.

13). Log timbers can also be easier to use in large headcuts where the size of the rocks needed may be too heavy for hand-build structures. See Appendix D for construction specifications.

Some key features:

• Make sure the logs are secured properly together and in place so they do not move or float in large flow events.

• Utilize filter fabric or woven geotextile material under and between the log layers. The fabric should also run vertical up the headcut wall to conserve soil moisture.

• Ensure that the critical pour-over location is the same elevation and has good contact with the top of the log structure to maintain moist and healthy vegetation. This is key to stopping the advancing headcut.

Figure 13. Log and fabric structure for treating headcuts before (top) and after

(bottom) installation. Photos by: Renee Rondeau

Technical Notes, Range May 2018

Grade control techniques

The following structure types can be utilized to counteract channel incision and actually raise the bed of an incised channel over time by promoting sediment deposition. In addition, these structures have the effect of slowing down the water to allow water to soak into the banks of the channel, supporting plant growth.

One Rock Dam

The one rock dam (ORD) is one of the most commonly used Zeedyk structures for channel recovery (Fig.

14). It effectively slows the flow of water, increases bank infiltration, captures sediment and helps recruit vegetation which can raise the channel bed elevation in gradual increments over time. An ORD is made of many rocks fit tightly together, but gets its name from being only one rock high (generally no more than a third the height of the bankfull channel).

Figure 14. One rock dams should have a footer for splash apron on the downstream end that extends far enough to intercept water pouring over the structure in a high flow event (denoted by yellow arrow). Photo by: Nathan Seward

Placement of ORDs varies with channel type and morphology. In a channel with natural meanders, place

ORDs at the natural area of deposition – the crossover or “riffle” in a riffle-pool stream sequence (Fig.

15). Look for sites where the structure can facilitate water slowing and soaking into adjacent banks, or for places where raising the bed elevation over time might assist in reconnecting the channel with its floodplain or subsurface hydrology. See Appendix E for construction specifications.

Figure 15. One rock dam plan, profile, and cross-sectional views (Sponholtz and Anderson 2013; figure courtesy of C.

Sponholtz). Note how ORDs are placed at the meander crossover or riffle.

Some key features:

• Build a footer for splash apron on the downstream end that extends far enough (2x the height of the

ORD) to intercept water running quickly over the structure in a high flow event.

• Fit rocks together tightly, all at the same height, to create a relatively uniform surface on top.

• Extend the bankside edges of the structure up the bank a bit to facilitate water going over the structure and not around it.

Technical Notes, Range May 2018

Filter Dam

The filter dam is a structure that is used to raise the bed of a gully by temporarily impounding shallow water, allowing it seep through the rock slowly, thereby trapping sediment (Fig. 16). Filter dams consist of three zones of carefully placed rock ranging from large boulders on the downstream edge, smaller boulders in the middle, to cobble on the upper end. Filter dams pond water longer than ORDs and were used only in limited situations in the Gunnison Basin where a ponding effect was desired to raise the channel bed and reconnect floodplains. For more information on potential filter dam applications and construction specifications, see Zeedyk and Clothier (2014).

Flow dispersal techniques

The following structure type is used to spread flow across the landscape or used to reconnect stream channels with their floodplains.

Media Luna

The Media Luna (half-moon in Spanish), originally designed by Van Clothier, is a curving rock structure primarily used to manage overland sheet flow. While this type of structure can be created to collect and concentrate sheet flow (tips down; Sponholtz and Anderson 2013) they are most commonly used to spread sheet flow across a wider surface (tips up; Sponholtz and Anderson 2013) (Fig. 17, 18). See

Appendix F for construction specifications.

Figure 16. Filter dams temporarily impound shallow water but allow water to seep through the porous structure, thereby capturing sediment. Photo by: Betsy Neely DSC-0886

Technical Notes, Range May 2018

Some key features:

• This structure type requires establishing accurate level grades with either a string level or a laser level because the tops of the rocks must be perfectly level for the structure to function properly.

• First layout and stake the contour where the structure is to be built, and then build the downstream row of rocks to match this level.

• Fit the rocks together as tightly as possible and utilize small gravel (or plants, sod) to fill gaps if possible.

Related techniques

Although not the focus of this publication, there are a few other Zeedyk techniques and associated practices that may be helpful to consider when restoring a stream or meadow reach. Refer to referenced publications for detailed technical information on how to design and implement these techniques.

Drift fences: Trailing up and down the valley bottom by domestic livestock and wild ungulates can compact soils, form trails over time that trap runoff and start gullies that de-water meadows. The drift fence is a linear fence segment, built perpendicular to the valley bottom or stream channel, to discourage excessive trailing. The fence segment spans the valley bottom with the ends either at the meadow/upland

Figure 17. The media luna with the structure tips pointed upvalley helps evenly spread out overland flow. Figure from Zeedyk et al. (2014)

Figure 18. Media luna (looking upvalley) being used to spread sheet flow; note structure is placed on contour with uniform surface. Photo by: Shawn Conner

Technical Notes, Range May 2018 interface or wholly in the upland. This obstruction in the valley bottom serves to interrupt the trailing animals, and forces them up and out of the meadow. The drift fence does not exclude livestock or wildlife from utilizing the meadow areas; it just interrupts the damaging trailing of the valley bottom. Refer to agency standards and guidelines for fence specifications and consider the need for wildlife-friendly design features (e.g., high-visibility markers).

Low water crossing: Roadway crossings of wet meadow areas can have dramatic detrimental results in the form of excessive rutting and erosion. In areas where roadways or recreational vehicle trails must cross meadows, an effective treatment is the low water hardened crossing. These treatments can take a variety of forms, depending on type of travel, frequency of use and other considerations. The low water crossing can be used as an opportunity to spread and distribute flows across a wider area, rather than the traditional method of installing a culvert which can concentrate flows and dewater adjacent areas. For details, see Zeedyk (2006).

Road re-grading: Another potential practice to consider is how runoff can be used to benefit meadows when re-grading roads. Often roadways were established in the path of least resistance, which meant they went right up the valley bottom and through the meadows. While it is preferable to relocate roads out of wet areas and into the uplands, roads that cannot be moved can still be maintained in a way that provides some benefit to the wet meadow system. For more information, see Zeedyk (2006).

Worm Ditch: The worm ditch is a treatment technique that is often used to enhance other structures by diverting flow and bypassing a headcut to starve it of water, or spreading concentrated flow into sheet flow onto a meadow surface. It is done by digging a very shallow, sinuous conveyance channel with a slope less than that of the land surface to reduce erosive power. It can be installed by hand or machine.

For details, see Zeedyk and Jansens (2009), Zeedyk and Clothier (2014), or Zeedyk and Vrooman (2017).

Plug and Spread: Plug and spread structures are used to reconnect ephemeral and intermittent streams with former meadow surfaces. The technique involves dirt work with a bulldozer and a skid steer. This technique can be used in areas where transporting rock is not practical or where channel incision is too deep to feasibly recover with hand-built rock structures. These structures are most effective in low gradient systems with wide floodplains and broad valleys, as they can restore more acres of former wetland with a small number of structures. For details, see Zeedyk (2015) and Zeedyk and Vrooman

(2017).

Tree Length Log Mat: Tree length log mats are grade control structures used in small watersheds to promote sediment deposition, widen the incised channel, and raise the channel bed. This structure type has not been utilized to date in the Gunnison Basin, but it may be something to consider in other

Technical Notes, Range May 2018 sagebrush rangelands where wood is more readily available than rock (e.g., pinion-juniper removal areas or burned areas). Installing log mats quickly after wildfire, and before first the storm, helps maximize sediment capture and reduce gully erosion. As opposed to traditional log-drop structures, tree length log mats have logs placed parallel to the channel, not perpendicular, with tree bases pointing upstream which helps filter flow and capture sediment without serving as just an impediment to flow. For details, see

Zeedyk and Clothier (2014).

V. Project planning

Whether at the scale of an individual ranch or a watershed, projects require thorough planning before structures are installed to maximize the likelihood of success and make efficient use of limited resources.

While Zeedyk techniques are relatively cost-effective and low-risk when compared to other approaches to treating headcuts and gullies, they still require considerable investment of time and effort to install and maintain. Careful planning is needed to ensure structures are well-placed, functional, and minimize unintended impacts. Good planning also helps make sure regulatory permits and consultations are secured well in advance, and materials, contractors, and volunteers are in place and ready to go during desired work windows. Taking an interdisciplinary, community-based approach is recommended and beneficial for successful implementation. Listed below are a few key aspects related using Zeedyk structures for meadow restoration based on experiences in the Upper Gunnison River Basin (for a summary of lessons learned, see Appendix G).

Goals and objectives

Developing a shared vision among project partners and articulating long-term goals and objectives should be done early in project planning. This not only helps keep partners on the same page, but it informs prioritization and site selection and provides a way to gauge project success. Goal/objective descriptions should go beyond just ‘stopping erosion’ or ‘installing structures,’ and instead focus on the desired hydrologic or ecological outcomes of the treatments. Emphasizing anticipated vegetation responses provides one meaningful way to determine if structures are achieving desired objectives within a reach.

Prioritization

While many project conversations start by visiting a particular sore spot on the landscape, it is always a good idea to zoom out for a moment to consider how that site compares to other restoration opportunities in the area. Many drainages impacted by headcutting and gully erosion across sagebrush rangelands would benefit from Zeedyk restoration techniques. However, resources, funding, and capacity are often limited, so it is important to be strategic about where you work and prioritize sites with the greatest potential for achieving desired outcomes using these techniques. Whether working with multiple partners to restore meadows at the watershed scale, or working with an individual landowner, conducting a site-selection analysis based on project goals can be a helpful exercise to evaluate potential restoration reaches. Using widely-available GIS spatial layers, combined with locally-defined priorities, can help project partners identify and narrow sites for on-the-ground evaluation.

Goals/Objectives Example: Gunnison Wet Meadow Restoration and Resilience-Building Project

Vision: Natural wet meadows and riparian habitats within the sagebrush landscape of the Gunnison Basin are resilient and support a sustaining population of Gunnison sage-grouse and other species, biological communities, ecosystem services and livelihoods in the face of a changing climate. Sustained and long-term community commitment to stewardship of wet meadows and riparian areas helps nature and people adapt to a changing climate.

Overall Goals:

1. Increase ecosystem resilience to climate change by restoring hydrologic function of priority wet meadow and riparian habitats within the sagebrush landscape at a scale large enough to help the

Gunnison sage-grouse, neo-tropical migratory birds, big game species and people who depend on these habitats for their livelihoods cope with projected impacts of a changing climate.

2. Build a sustainable and enduring program to increase restoration across the Basin.

3. Ensure scientific rigor of this project through a long-term monitoring program.

4. Develop and evaluate cost-effective tools, methods, and planning to help scale up the project.

5. Share best practices and lessons learned to encourage application of methods within and outside of the

Basin.

Site-Specific Objectives:

Kezar Basin: Restore stream flows in wet and mesic meadow habitats, reverse incision and active gully expansion, and create barriers to reduce trailing by livestock and wildlife in riparian zones.

• Management objective 1: Increase the average cover and density of native sedges, rushes, willows, and wetland forbs (obligate and facultative wetland species) in the restored portion of the treated properties by at least 20% within 5 years after treatment.

• Management objective 2: Decrease the average cover of rabbitbrush, sagebrush, and other upland species in the restored portion of treated properties within 5 years after treatment.

Technical Notes, Range May 2018

This type of approach was applied successfully in the Gunnison Basin to assist land managers and landowners identify areas in need of restoration and most likely to respond favorably to treatment. The

Nature Conservancy and the Gunnison Basin Project Team developed a climate-informed GIS process to identify stream reaches within critically important Gunnison sage-grouse habitat that offer the greatest potential to respond favorably to the restoration (for description of methodology, see: TNC and GCWG

2017). The team created a simple restoration index for riparian areas along small streams using publicly available satellite imagery. This restoration index calculated the area of very green vegetation (a proxy for vegetation health and productivity) between wet and dry years.

Riparian areas were prioritized based on how much this green vegetation area remained stable or decreased during dry years. For example, riparian areas with very green vegetation in both wet and dry years indicate sites that are more likely to be well-connected to their floodplains, functioning, and more resilient to drought. Riparian areas that only produced very green vegetation in wet years, but not in dry years, indicate that hydrologic connectivity may be impaired but recoverable. In these cases, incision was not too severe, which allowed for sites to still function during wet years. This information highlighted potential opportunities to increase drought resiliency through restoration. To further narrow sites that were most relevant to the Gunnison project goals, the team also used additional data, such as, distance to sage-grouse leks (< 2 mi) and brood-rearing habitat. This helped the team reduce the scope of potential treatment reaches for field investigation (Fig. 19).

Site evaluation and inventory

Once high potential areas are identified through a GIS analysis, interdisciplinary partners (e.g., biologists, hydrologists, restoration experts, land managers) should be engaged to narrow down the list of potential stream reaches to visit based on local knowledge. Criteria to consider during this phase may include

Figure 19. Results of the GIS prioritization analysis in Gunnison Basin.

Figure by: Teresa Chapman

Technical Notes, Range May 2018 things like: land ownership and willingness of landowners/managers, accessibility, opportunities for efficiently scaling-up beyond a single reach, sources of water, geographic representation, habitat condition and values, and status of permitting and planning documents. The results provide a starting point for field evaluation to further prioritize stream reaches for on-the-ground treatment.

Next, the restoration team should conduct field visits to evaluate the condition of the site, identify…