Flood Recovery Blog Series Post 5 Resilient Stream Restoration Design: The Streamcrest Example

May 13, 2019

Author: Julie Ash

Post Date: 5/8/2019

Contributed by Julie Ash, Stillwater Sciences

Dear Reader: if you’ve been following CRA’s 2013 Flood Recovery Blog Series since Post 1, with the Streamcrest project highlighted as a flood recovery success story since Post 3…well then, first of all, we’re so glad to have you with us. Secondly, you might be wondering if the Streamcrest project could truly have gone as well as it’s been described in these blogs. In Post 3, Luke Swan laid out a story from mere days after the 2013 flood through the end of the 2014 master planning phase, detailing the Streamcrest neighborhood’s impressive ability to quickly absorb complex technical information (which wasn’t always happy, easy to swallow news) and to help move recommendations forward. In Post 4, Jessie Olson wove the story of a community rallying around a common goal, building and maintaining trust, and uniting to help build a more resilient future for themselves and their river. In this post, I’ll share the story of analysis and design for Streamcrest…and yep! you’ll hear again how Streamcrest navigated its hoops and hurdles. Not without drama, however. Streamcrest had its fair share of challenges and last-minute changes, all set to an astonishingly fast timeline to meet funding requirements. But the story remains the same…the Streamcrest project navigated all hurdles, ultimately prevailing because of the high level of trust between and the strong commitment from all partners involved. Hopefully the Streamcrest blog series hits the inspirational mark for you and perhaps helps future projects stay the course for delivering resiliency for our rivers and the communities along them. I am grateful for the honor of being part of the Streamcrest story of community and flood recovery success – and excited to share its design story!


My guide in writing this blog is to try to strike a balance between offering a fairly readable “story” about analysis and design – and conveying the technical rigor that supported the Streamcrest design. I believe I’ve landed somewhere between motivational fairytale and scientific design basis report (since this is quite a wide spread, my confidence is fairly high.)

Warning: This blog post is lengthy and includes a fair amount of detail about the “nuts and bolts” of designing a restoration project, including the hydrologic, hydraulic, geomorphic, and sediment transport analyses that supported the Streamcrest design. Please join us as we dig into the details. For those of you who want a quick overview of Streamcrest project design elements, skip to the wrap-up section here.

So, let’s start at the beginning with the goals that were handed to the Streamcrest project by its funders and the precursor phase to design, which is development of a solid understanding of the system and its driving fluvial processes.

Goals and System Understanding

The Lefthand Watershed Oversight Group (LWOG) was given project goals for Streamcrest by its funding sources:

  • Natural Resources Conservation Service (NRCS) Emergency Watershed Protection (EWP) Phase 2 program;
  • Housing and Urban Development (HUD) Community Development Block Grant – Disaster Recovery (CDBG-DR) program, administered for Colorado by the Department of Local Affairs (DOLA); and
  • Critical match funds from the Colorado Water Conservation Board (CWCB), the agency that stoically took the reins to shepherd Colorado through its flood recovery.

Streamcrest’s project goals were to reduce threats to life and property and increase resiliency for better future performance by reducing damage in future floods and increasing stream health and function in periods between flooding.

These goals sound fabulous, but actually delivering on them requires more detailed targets, and furthermore it needs targets tailored to this special and individual site. Without concise objectives identified as the agreed-upon means to meet the stated goals, expectations are extremely difficult to manage, particularly when many parties are involved, representing a wide variety of land use needs and wants.

Specific objectives set for Streamcrest to meet its protection and resiliency goals were to:

  • increase floodplain connection by removing excess sediment and incorporating floodplain benches;
  • stabilize eroding banks;
  • provide offset hard protection at critical assets;
  • increase stream health (including pool habitat) through riffle-pool-run sequencing and boulder clusters; and
  • re-establish native riparian vegetation.

Ok, now we’ve got some clear direction!

The next thing you need for delivering on lofty goals is a comprehensive understanding of the complex fluvial system you’re looking to improve. While this is always needed, the flood-altered state of our stream corridors following the 2013 flood made this even more critically important. The reason is that post-flood channel morphology was a result of an extreme disturbance event, which made it difficult to relate the observable channel conditions to a condition that occurs during more average years.

This challenging post-flood situation took some design approaches off the table because the desired restoration condition to maximize river health and function (including channel dimensions, floodplain connection, etc.) did not exist in the watershed due to the profound effect of the large flood event. Restoration techniques such as using reference reaches were therefore not applicable as a useful design tool in this situation. The Streamcrest design team met this challenge using a process-based design approach that employs multiple lines of evidence to understand and work with driving process dynamics to jump start the natural recovery process and successfully navigate ongoing channel response through time.

The quick summary of what the design team needed to know about Streamcrest for effective analysis and design is that the neighborhood sits on a dynamic landform called an alluvial fan, a feature formed where steep, confined, mountain channels transition to lower gradient valley and plains channels, dropping sediment loads and shifting locations, creating a fan-like landform. (Credit to Luke for that description – see Flood Recovery Blog Series Post 3).

The 2013 flood, through channel avulsion and debris flow processes, delivered a substantial quantity of sediment and debris to the neighborhood, with deposition up to seven feet deep in some areas. The sediment and debris plugged undersized box culverts at US 36, exacerbating the sediment dropout that would ordinarily occur in this reach because it is less confined and flatter than upstream canyon reaches. The extensive deposition increased channel avulsion (movement) and bank erosion upstream of the culverts, causing substantial damage to neighbors’ homes during and after the flood. Backwatered by US 36 culverts, floodwaters found a straighter, easier flow path through its floodplain – running right through, around, and along homes and lawns and neighborhood roads.

Following the flood, the creek began scouring down through the deposited sediments, forming a wider, straighter, and higher gradient channel than existed prior to the flood. Left alone, the channel would continue to dissipate energy vertically, incising and expanding. With homes in close vicinity to the creek, uncontrolled adjustment on this scale was determined to be unacceptable and therefore proactive restoration measures were necessary.

Rigorous Analysis using Multiple Lines of Evidence Approach

Analyses supporting the Streamcrest design used a ‘multiple lines of evidence’ approach, meaning that industry tools currently available for understanding the driving mechanisms of fluvial systems were evaluated for applicability to the Streamcrest reach (technical applicability) and to the project scope and scale (time and budget applicability) and several applicable methods were selected for use. The strength of the multiple lines of evidence approach is the ability it affords to understand level of confidence in results. Fluvial systems are dynamic and complex, responding to extensive diverse and interrelated factors (both ecological and anthropogenic) and this equates to high uncertainty for analyses seeking to explain driving mechanisms in simplified terms.

By employing multiple lines of evidence, analysts can identify converging or diverging information and trends. Converging results increase the level of confidence in system understanding. While higher levels of confidence are valuable and preferred, awareness of lower levels of confidence is equally important because it allows designers and project proponents to build in greater accommodations to address the uncertainty. For example, additional conservatism can be applied and, if possible, more budget can be obtained to expand protection measures. At a minimum, efforts to manage expectations of landowners and other stakeholders on future performance, risk to life and property, and maintenance requirements must occur.


So things started off well enough for Streamcrest’s analysis and design process. Like the goals and development of system understanding, initial analyses were non-confrontational. Let’s go to hydrologic analysis and survey tasks next…

Hydrologic Analysis

Design analysis and specification of restoration treatments are built on and significantly affected by hydrologic inputs. This dependence conveys the importance of ensuring use of the best available hydrologic information and investment in site-specific hydrologic information, if and when that is warranted.

Hydrologic analysis for the Streamcrest project included calculations from a range of available data and methods, consideration of level of confidence in results, and then selection of most appropriate base flow and peak discharge estimates for return intervals from the 1.5- to 100-year events. Results of hydrologic analysis indicated a moderately high level of uncertainty for peak discharge rates for the Streamcrest reach, with uncertainty increasing as flow rates get higher. Uncertainty was due in part to variation in data sets’ inclusion of the 2013 flood event (which was dramatically higher than other recorded events), as well as short and fragmented periods of gage data record. Awareness of uncertainty levels was an important design consideration for the project, warranting sensitivity analysis for critical features and selection of structures with greater ability to adjust with variable conditions and changes over time, as the upper watershed continues to respond to the large flood event.

An existing hydrologic study from 2014 was determined to be the conservative source for 10-year and larger peak discharge estimates. For smaller peak flow rates, gage flood frequency analysis was deemed to be the most reliable source of data. Additional analyses for smaller return interval events included StreamStats and rating curves to extrapolate from available data sources.

Applicable data for base flow estimation was sparse due to diversions just upstream, loss of gages during the flood, and flows diverted into the basin from South St Vrain Creek. To address this lack of usable data, the design team developed a flow duration curve using the U.S. Army Corps of Engineers (Corps) Statistical Software Package HEC-SSP and mean daily discharges for a nearby (still intact) USGS gage. The resulting flow duration curve is shown below, and the base flow was defined as the discharge exceeded 50% of the time.  

Topographic Survey

As with hydrologic data, design analysis and specification of restoration treatments are heavily affected by the topographic information used for the project. The Streamcrest project made substantial investment to obtain current and detailed survey data because changes to the land during and after the flood were dramatic, rendering year-old and sometimes even months-old data obsolete. Base mapping for the Streamcrest project was developed from a new ground survey of the channel (completed as part of the project in July 2016) and a photogrammetric survey of the overbank areas. The topography was merged with existing 2014 Light Detection and Ranging (LiDAR) for upland areas to create existing conditions topography. The result was a quasi-3D virtual river environment in which hypotheses could be tested with hydraulic simulations.


…ok, we’re about to dive into hydraulic analysis, which is where we take selected flow data and route it through compiled topographic data and start making predictions about how water will behave, where it will go, when it will go there, how deep it will be, etc. It doesn’t take a rocket scientist to guess that things can start getting more controversial here, particularly when we have homes and roads in close proximity. Let’s go there anyway…

Hydraulic Analysis

One-dimensional (1-D) hydraulic analysis was conducted for the Streamcrest project using HEC-RAS computer software. Results of the hydraulic modeling provided inputs to hydraulic design, sediment transport, and channel stability calculations, and were used to evaluate changes in flood levels resulting from the project for the required Floodplain Development Permit (FDP). Understanding the flow complexities through modeling is crucial for understanding flood risk, geomorphic risk, the subsequent communication of that risk to residents along the creek, and the effect of the proposed design.

(we’re about to geek out for a second, stick with me…)

1-D models make extensive assumptions in order to simplify hydraulic complexities. Streamcrest had complex overbank flow characteristics that made the inability of the 1-D model to compute transverse variations in water surface elevations, velocities, and momentum a significant problem for accurately modeling flow behavior. The problem was compounded by the high level of risk at the site because homes and roads are in such close proximity to the creek.

And so we’ve reached one of the bumps in the happy Streamcrest story.

Based on understanding of Left Hand Creek at Streamcrest from site visits, geomorphic assessment, and sediment transport analysis (more on those in the following sections), we knew that a large earthen berm installed post-flood as part of emergency response was exacerbating problems for the neighbors and increasing risk of damage in future floods. We wanted to remove the berm as part of proposed grading activities and return the creek to a well-connected floodplain condition, with preferential overflow paths provided to route flood flows as safely as possible past neighbors’ homes. Our recommendation met with strong resistance from some neighbors because the berm had been presented as a protective measure right after the flood and because a big, solid mass is pretty comforting when you want to block something. It’s counterintuitive, and therefore a tough message to sell, that open space (providing room for the river) will actually protect you better than solid mass. It is very often true, however.

The design team and LWOG realized that we needed better “proofs” to share with the neighbors so they could understand design team recommendations. Due to its limitations (recall geek-out discussion on inability to compute transverse variations), the 1-D hydraulic model was not able to represent flow behavior as it overtopped the berm, accessed the floodplain behind it, and started following multiple flow paths. To overcome the problem, we brought in two-dimensional (2-D) modeling.

As Jessie described in Flood Recovery Blog Series Post 4, LWOG worked with the neighbors and organized a Saturday morning neighborhood potluck meeting at Mark’s house to allow the design team to present 2-D modeling results and the case for berm removal. We showed video of the time-lapse runs that produced by the 2-D modeling software, so the neighbors could see flow moving into new areas (their yards) as floodwaters start increasing during storms or spring runoff. The better accuracy of the 2-D modeling (and the time-lapse video capability) had a lightbulb effect for folks because they watched flow patterns on the screen that closely matched their observations during the long week of the 2013 flood. Once we gained that credibility, we were able to run model scenarios for the “with berm” and the proposed “without berm (with connected floodplain and safest overflow routing)” conditions to demonstrate how our recommendations would best reduce flood risk to their properties.

This Saturday morning technical presentation allayed neighbors’ concerns and brought them on-board with the recommended berm removal. This endeavor also added to the trust relationship between the neighbors and LWOG and the design team. Even further, not long after the Saturday meeting, one of the previously resistant owners made a substantial donation to LWOG and its future efforts. Now that is a win-win!


Geomorphic Assessment

It’s tricky deciding the order in which to present hydraulic, geomorphic, and sediment transport analyses because they are iterative, both informing and depending upon the results from the other analyses. This reality ties back to the multiple lines of evidence approach discussed earlier. When myriad analyses start providing insights that suggest similar conditions and similar trends, it increases the level of confidence that we’re on track for understanding the important process dynamics for the site.

From the start of the Streamcrest project, the design team benefitted from geomorphic information provided by the 2014 Left Hand Creek Watershed Master Plan. The master plan developed process diagrams using River Styles, providing key insights as to how different reaches of Left Hand Creek fit into the larger watershed context. The Streamcrest reach is circled below on the Plains Process Diagram from the master plan. This early geomorphic understanding helped guide field assessments and hydraulic and sediment transport analyses. In turn, output from the hydraulic analyses provided required input for calculations on sediment transport.

The process diagram shows the watershed position of Streamcrest, which is located near the canyon mouth, defined as a partly confined, wandering channel. A fully confined setting occurs farther upstream, where hillslopes limit the meandering and lateral adjustability of the channel. Remember from earlier discussion, that this transition zone sees abrupt change from narrower and steeper upstream to wider and flatter through Streamcrest, which creates a natural depositional zone as the creek spreads out across the available floodplain, dissipating energy and dropping its sediment load.

Following the 2013 flood, the channel at Streamcrest began scouring through the vast deposit of new sediments, making the floodplain increasingly perched and hydrologically disconnected from the channel and creating vertical, unstable banks with degraded aquatic and riparian habitat conditions.

The geomorphic assessment provided guidance for specifying proposed improvements, including the reach’s depositional and response tendencies, as well as the future trajectory for the reach. Designers knew it would be important to specify treatments for Streamcrest that could accommodate ongoing adjustments as reaches upstream of the project continued to respond to the flood disturbance, elevating sediment loads to Streamcrest as channels scour through newly deposited sediments and cause new and exacerbated erosional areas.

Additional design guidance was gained from sediment transport analysis, which included capacity estimates for each reach to compare potential erosion or deposition for existing and proposed conditions and informing treatment design to help balance continuous sediment conveyance through the Streamcrest reach.

So let’s dig in on sediment transport next…

Sediment Transport Analysis

Sediment transport capacity is defined as the quantity and rate of sediment that a river is able to transport at a given flow. Capacity is a function of the shear stress on the river bed and the range and relative quantities of sediment grain sizes on the bed surface available to transport downstream. Using hydraulic modeling results and grain size distribution data sampled at representative locations, transport capacity at Streamcrest was estimated using Parker’s (1990) surface-based, bed material load equation for coarse bed rivers. Transport capacity was calculated for a given discharge for each grain size interval and then scaled based on the fraction of each grain size interval represented in the bed. Sediment gradations for Streamcrest (and upstream and downstream projects) are graphed below and show key particle sizes (e.g., 50% Finer (D50), 84% Finer (D84)) used for analysis and design.

Sediment yield in a river (sediment mass exported from a reach) is driven by the entire range of competent flows that fluctuate continuously from year to year. Theory says that coarse bed rivers such as Left Hand Creek tend to mobilize their bed at the annual flood and larger events, but the state of the watershed meant that the design team could not rely on these assumptions for this project. Considering sediment continuity during these flood events, the relative rate and quantity of sediment moving in each reach, is important to understanding how the system will behave.

Equilibrium bed slope analysis was conducted as a guide to determine appropriate longitudinal profiles to understand reach slopes and inform sediment balance calculations. This analysis served as an additional line of evidence in support of design recommendations. The Streamcrest sediment transport analysis averaged the hydraulics of all the cross sections contained in each defined reach from the 1-D hydraulic model to represent the hydraulics and sediment transport capacity over the entire reach.

The results for the 2-year recurrence flow (Q2), an important design flow, are shown below. The plot shows the estimated reach-averaged sediment transport capacity for existing condition (EC) and proposed condition (PC) models for Streamcrest (the “SC” results). Results for upstream and downstream projects, the Upper Left Hand (“LC”) and Ranch reaches are also shown in the plot. Because these capacity estimates have several limitations, they were used solely as relative comparisons to inform and support design decisions (i.e., they were another line of evidence). A relative balance between the transport capacity of a reach and the sediment supplied from upstream can offer insight to the potential erosion or deposition that will be seen in the channel. 

The sediment transport results for Streamcrest specifically directed designers towards treatments for the upper section of channel that addressed higher erosion potential in the upper, straighter, steeper reach by reducing transport capacity for the section to bring it as close as possible to balance with the downstream section. The results directed designers towards treatments for the lower section that dealt with accumulations of fine materials. Unfortunately, we could not fully restore depositional fan processes because of the proximity of the homes.

…and so finally we now have all the information we need to move onto design!

(…actually, that sounds nice for storyline and works well for the flow of this blog, but in reality design has been progressing alongside these interrelated hydraulic, geomorphic, and sediment transport analyses.)

Design Treatments

As described above, the degraded conditions to be addressed by the project included vertical, unstable banks, lateral confinement, homogenous channel morphology, and low aquatic and riparian habitat quality. The existing condition in the project reach was almost one continuous riffle. Pools were rare and typically small and shallow when present. Banks were actively eroding and destabilizing temporary emergency protections emplaced after the flood. Floodplains were almost completely devoid of trees, shrubs, ground cover, and even soil in some areas. The straighter post-flood channel had significantly steepened gradients, contributing to ongoing post-flood channel adjustment.

The overarching design strategy for Streamcrest was to increase conveyance capacity of the channel, lower the channel bed while maintaining as much floodplain connectivity as possible, and increase channel complexity. Treatments were designed to work with fluvial processes to jumpstart the recovery process, providing benefits for but also beyond asset protection, including increased fish and wildlife habitat, improved water quality, and avoidance of the long-term economic and safety liabilities and maintenance costs associated with hard-engineered structures.

Streamcrest design included large wood structures and pool-riffle sequences with natural rock gradations for diverse instream conditions and ability to adjust with ongoing watershed adjustment.

The Streamcrest design used both direct and indirect treatments. The direct approach included grading to modify or remove berms and improve or add armoring to protect infrastructure.

The indirect approach, often referred to as ‘restorative flood protection’, employed natural features such as vegetation, wood, and connected floodplains to store and slow the flow of water and sediment, improving conditions during low flow and high flow for the Streamcrest reach and for downstream reaches as well.

Examples of restorative flood protection incorporated into the design include reconnecting incised channels to their floodplains by removing or reshaping large berms, and re-establishing stable instream wood and riparian vegetation to reduce effective shear stress within the channel and increase inundation frequency and retention times of overbank flows.

To specify the most effective design treatments, the design team started with proposed grading for widths, depths, and longitudinal profiles appropriate to reduce transport capacity in the upper channel section within site constraints (for better balance with the downstream section) and to increase sediment transport under low flow conditions in the downstream section to naturally flush out the accumulations of fine materials. The predicted median grain size, D50, to achieve equilibrium at the 2-year peak discharge was estimated using Shields method for incipient motion. The equilibrium bed slopes were estimated by applying the Mannings and Shields equations.

Streamcrest had a substantial budget, so the project was able to include all the selected improvements without cutting treatments to meet budget limitations—something a majority of restoration projects do have to accommodate.

Installed pool-riffle sequences at Streamcrest.

The proposed bedform sequence was a series of pool-riffle sequences. Because of the straightened alignment, slopes of riffle crests were increased to encourage pool scour. Riffle crests at the upstream end rely on helical flow of the bend to scour the pool. Parameters proposed for each pool, riffle, and run were varied from targets to best accommodate existing pool-riffle features and to minimize grading disturbance.

Proposed channel geometry design used the lower return period discharges (Q1.5, Q2, and Q5) and baseflow for channel sizing, low-flow channel dimensions, determination of bench elevations, and setting overflow channel engagement points. To the extent possible, the channel geometry was designed so that the 2-year discharge could be conveyed by the bankfull channel. Hydraulic geometry equations were used for estimating bankfull width and mean depth, factoring in bank vegetation, bank cohesion, and sediment load. Given the characteristics of the project site, the bankfull geometry was calculated with the assumption of relatively thin bank vegetation. The bankfull channel was designed for multiple stages below the 2-year discharge, including shaping for narrower baseflow widths and to specifically encourage a “low flow” channel that concentrates stream flow to improve habitat quality and facilitate fish passage during low flow periods.

In addition to channel grading to influence changes in transport capacity, the design also used roughness and floodplain connectivity improvements. Form roughness was achieved through the pool-riffle sequences. Stable large wood features, willow/branch trenches, and native revegetation delivered additional roughness to the reach. A multi-stage channel cross section with floodplain benches and new overflow channels increased floodplain connectivity and flood conveyance and helped deposit sediment along the margins of the channel, best accommodating flows from low flow to moderate flood events. Floodplain benches were graded to provide inundation between the 1.5- and 2-year discharges.

Additional details of the design specified to accommodate the ongoing adjustments in the watershed included riffle crests with natural rock gradations to allow adjustment without failure of the structure or loss of intended function. Pools were designed with self-scouring features, including minor constrictions at riffle ends and strategically placed boulders and large wood protrusions.

Streamcrest design included floodplain benches and overflow channels for floodplain connectivity.


Implementation of the Streamcrest flood recovery and restoration project was completed in the summer of 2017, so improvements have been in place almost two years at the time of this blog (which is spring 2019 prior to peak flows). The project has experienced one spring runoff event in 2018. Worth noting is that 2018 was a low snowpack and runoff year in the watershed, so newly installed treatments weren’t tested on the larger streamflow front. Also of interest is that 2019 runoff forecasts from NRCS and NOAA River Forecast Centers are calling for near-average (90 to 110%) or above average (110 to 130%) spring-summer runoff for most forecast points in Colorado, so the 2019 runoff may not be the big test either. The flip side to this is that, without seeing some larger flows, the newly installed channel features haven’t been flushed or conditioned. Channel features were designed for some fluctuation with inputs of water and sediment, and a moderate flood event or two would go a long way to enhancing the appearance and function of the site.

Large wood features are important for aquatic habitat (cover, shading, and cooling) and they also do a great job racking small wood delivered from upstream and helping support riparian vegetation

Streamcrest has experienced periods of low flow since construction was completed, so the deeper pools and cover logs and boulders installed by the restoration project have been valuable for aquatic species. Riparian vegetation is also important for shading and cooling during low flow periods, but revegetation efforts take a few seasons to fully establish before they start providing substantial shading and cooling functions. This delayed performance increases the importance of strategic wood and boulder installations for habitat value immediately after project completion.

The revegetation at Streamcrest does provide immediate benefit via soil stabilization and nutrient supply functions and these will become more and more robust as the vegetation establishes over time.

Streamcrest’s incorporation of large and small wood along the channel and on floodplain benches for roughness has performed well for soil stabilization in the immediate post-construction period, which can be very challenging for resisting rill erosion because vegetation does not establish immediately. Rilling is the removal of soil by concentrated surface water flow and commonly occurs between newly-installed boulders and other harder features before establishment of vegetation and deposition of organic matter that would otherwise help to slow flow and resist erosion. The problem is compounded by the increased difficulty of establishing vegetation in tight spaces between hard features.

The use of large wood features for bank stabilization helps resist post-construction rilling that is hard to avoid with boulder bank protection that needs vegetation to establish between the boulders to resist scour

The use of wood features, with small wood and branchy materials, is a good way to avoid the post-construction rilling problem. Further, the propensity for wood features to accumulate wrack (small wood and other organic matter delivered from upstream reaches) creates a beneficial cycle of velocity reduction and erosion resistance to help with riparian plant establishment, which in turn helps reduce erosion.

Although the test of higher flows remains in Streamcrest’s future, the restoration efforts are showing signs of delivering the multiple benefits intended by this flood recovery project. Risk to neighborhood homes is reduced by extensive floodplain reconnection, overflow channels, and offset hard protection. Water surface elevations in the vicinity of homes were reduced by the project’s grading work and restored bedform complexity is helping moderate sediment loads, reduce geomorphic risk in future floods, and increase fish and wildlife habitat.

Eroding bank sections were protected with large and small wood features, which serve additional functions for stream health, including cover, shading, cooling, and detritus supply, and further risk reduction via local sediment storage along channel margins. The use of wood features and riffle crests with adjustable natural rock gradations reduce the long-term economic and safety liabilities and maintenance costs associated with hard-engineered structures.

The restored pool-riffle sequences and habitat boulder clusters also serve to improve aquatic habitat heterogeneity and ecological function for the reach. Lastly, the newly installed native plants are getting established and will bring everything together on the site, fostering healthy ecological exchanges laterally and longitudinally for the Streamcrest river corridor and for the long-term benefit of the people living along it.

So then…what is up next for Streamcrest? LWOG is focusing on long-term monitoring and their program includes sites at Streamcrest. The CWCB has implemented a long-term project effectiveness monitoring program that includes baseline data collection and monitoring of 30 or so flood recovery projects (of the 100+ projects completed) and Streamcrest is one of their high-priority sites. Everyone involved with Streamcrest is looking forward to seeing how it adjusts and functions – how well it stands the test of time!


Colorado Riparian Association