Restoration efforts are underway worldwide to restore, improve, and preserve rivers’ ecological conditions. Restoration aims to minimize and limit human-caused environmental damage and bring rivers back to a functioning ecosystem habitat for threatened species. Federal, state, and local governmental agencies who participate in these projects are increasingly challenged to justify their approaches and expenditures. At the same time, very little research has been conducted to demonstrate how successful river restoration projects are in meeting their desired and planned objectives. Here, I provide some guidelines to quantify and measure the success of river restoration projects. The focus here will be on ecological and hydrological objectives and will include a discussion on the uncertainty and risks of the post-project monitoring process. I demonstrate these guidelines in light of a restoration project at the Weber River, UT.
1. What is river restoration?
Restoration of river ecosystems can be best described as “the process of returning a river or watershed to a condition that relaxes human constraints on the development of natural patterns of diversity” (Frisell & Ralph, 1998). This definition avoids the often unrealistic or infeasible attempt to return to pre-disturbance conditions. River basin management decisions should therefore be based on ecological effects of stressors on ecosystem (e.g. altered food webs, excess competitors) rather than on the stressors themselves (e.g. chemical and pollutants, nutrients, etc.). However, since most rivers experience multiple stressors, understanding and analyzing complex ecosystems for the purpose of proposing management decision is challenging (Popovska et al., 2000). Hence, using a pre-defined set of indicators, or monitoring standards to measure the success of restoration projects might not always be suitable considering that different pressures might have different impacts on the ecosystem and therefore require site- and time-specific metrics (Hering et al., 2010). Thus, managers need better tools to help them understand the complexity of ecosystems (Fig. 1) and the underlying uncertainty.
Figure 1. Cause and effect chain of factors influencing river systems (adapted from Loucks et al. 2005)
2. Why monitoring? Monitoring in the restoration process
Though a gap still exists between the science and practice of restoration (Wohl et al., 2005), a systematic approach to monitoring and reporting project success should facilitate the communication between the scientific community and restoration practitioners, and vice versa (Bash & Ryan, 2002). Monitoring can help answer questions about projects overall progress relative to target objectives including, but not limited to:
- Is the project on the right track to achieve its target goals?
- How did the surrounding community benefit and/or contribute to the success of the project?
- Are the objectives set at the beginning of the project specific, measureable, attainable, realistic, and time-bound (SMART)?
- How did the objectives match available resources (e.g. budget, manpower, skills, and time)?
- What can be learned from this project to improve future water resources plans?
Though the benefits are significant, monitoring the success of restoration projects is rarely carried out in practice. Bernhardt et al. (2005) compiled a study of over 38,000 river and stream restoration projects in the US since 1990 and found that only 10% of the projects had a monitoring component as part of the project design. This means that the vast majority of restoration projects are not based on pre-designed, measurable objectives that can show physical or biological improvements in restored sites. Nonetheless, designing an effective monitoring system can be challenging and highly subjective (Giller, 2005). The success of a monitoring system relies on it being an integral component of the initial restoration project design (Ralph & Poole, 2003). This is best illustrated by defining project objectives in measurable and time-bound statements that makes them applicable for long-term data collection, recording and analysis.
3. Uncertainty in project monitoring
Uncertainty is an integrated component of environmental-related decision making (Mant et al., 2008). Uncertainty in river and riparian restoration is associated with lack of data and details or structure of the processes involved in making decisions on potential management alternatives. Such decisions require framing assumptions on the possible behavior of natural systems based on historical trends and past experiences and trying to minimize bias and errors. Uncertainties in defining restoration objectives and targets are rarely recognized, poorly quantified and seldom reported (Walters, 1997). The two major sources of uncertainty in the monitoring process. The first is the uncertainty caused by natural variability.
This uncertainty stems from the inherent fluctuations of hydrologic and ecological components of restoration projects make monitoring the change of different variables challenging. For example, data to support assumptions of ecological response of different species to changes in flow regimes is often unavailable. Assumptions are typically made based on empirical observations of species of interest on similar rivers. This introduces uncertainty that arises from spatial, temporal variability, and individual heterogeneity. The second source of uncertainty is caused by model formulation. This is a common source of uncertainty because our lack of knowledge to model natural systems is incomplete. Often, scientists use models to simplify the expression of natural processes. The exercise of model verification and validation helps clarify some uncertainty but does not eliminate it altogether (Clifford et al., 2008). For example, the estimation of Manning’s n constant, which describes energy reduction to boundary friction, is expressed in mathematical formulas that oversimplify channel shape for simplicity.
4. The Weber River Basin Restoration: a case study
The Weber River watershed in Utah encompassed 1.5 million acres of land in Weber, Morgan, Summit and Davis Counties. The watershed is bounded from the north and the east by the Bear River watershed, from the south by the Jordan River watershed and by the Great Salt Lake on the west (Fig. 2) (WBWCD, 2003). The river currently provides nearly 21% of Utah’s population with water for drinking and irrigation purposes. However, land and water development have degraded water quality in some areas and led to impairment of the health of its ecosystem (WBWCD, 2003). Human activities are the primary cause of the river degradation. Overgrazing, restricted and altered flows, fish blockages, nutrient loading, irrigation, in addition to urbanization and riparian area degradation are some examples of the human impacts upon the Weber watershed (WBWCD, 2003). A small portion of the Weber (1.1 miles) in Ogden has already been restored with three main objectives: 1. Improve community connection with the river (e.g. increase public access, recreational activities, and flood protection), 2. Enhance river appearance through trash removal and recycling, and 3. Sustain and improve ecological functions and habitat diversity. Although no predefined objectives or restoration plan were documented, the project was well-received by the public and considered successful.
Figure 2. Weber River basin map (UDWR 2009)
4.2. Challenges of monitoring in the Weber restoration
Efforts are underway to develop a more basin-wide restoration project for the Weber. In 2003, a Watershed Restoration Action Strategy for the Weber River basin was developed by the Weber Basin Water Conservancy District (WBWCD). The group is comprised of stakeholders who share an interest in improving the water quality of the river and restoring habitat (WBWCD, 2003). The Weber River Watershed Coalition and the WBWCD developed a strategy of 9 goals aimed at enhancing water quality and developing public outreach, education and support programs in the watershed, although the primarily focus is water quality and the plan is not a comprehensive restoration plan. In addition, although the strategy defines actions and a timeline for the implementation process, it neither presents quantifiable measures of the success of restoration targets nor a reference site towards the program’s ultimate goal of restoring and protecting the water quality of the basin. Nonetheless, such a strategy can be a substitution for a more comprehensive restoration plan for the Weber River.
Although SMART objectives are the core of defining success in monitoring, they are seen in the project design as “expensive luxuries” which do not add a significant value to the project (Skinner et al., 2008). Among other technical obstacles that the Weber restoration practitioners might encounter, stakeholder involvement substantially affects monitoring, either by contributing or constraining it, according to individual and organizational interests. In the Weber, restoration practitioners should acknowledge the following challenges of monitoring:
a. Lack of standards
One of the major reasons that monitoring in restoration projects is rarely performed is due to the lack of monitoring and evaluation standards. Many authors call for developing a widely acceptable and widely applicable scheme for monitoring restoration projects (Perrow & Davy, 2002). Recently Palmer et al. (2005) developed standards and guidelines to measure restoration success at the watershed scale. They propose a monitoring strategy based on the five following criteria:
- Restoration project design should be based on a guiding image of a more dynamic and healthy river
- Improving ecological conditions must be measurable
- Following restoration, river systems should be more capable of self-sustaining hydrologic, geomorphic, and ecologic conditions, and thus more resilient
- No lasting harm should be inflicted to the ecosystem in the construction phase
- Information on pre- and post-construction phases should be made available to concerned parties.
Such standards were widely accepted and refined by groups of river scientists and practitioners. Other strategies were proposed by Woolsey et al. (2007) to assess river restoration success in terms of both restoring the ecological attributes of river systems and achieving socio-economic targets. These standards serve as guidance for developing a monitoring plan for the Weber.
b. Defining reference sites
In most developed countries, naturally intact reference sites no longer exists (Giller, 2005). Pristine natural ecosystems rarely exist in industrialized countries and therefore reference sites for restoration are difficult to find. This seems logical as most restoration efforts were triggered only after the human impacts on the environment were widespread. Hence, identifying a reference site is often very challenging because each restoration site is unique in its natural variability and complexity. Using reference sites is also undesirable as it may lead river managers to “misplaced confidence” in the predicted outcomes of restoration actions (Hughes et al., 2005). Therefore, there is an increasing trend to move beyond defining a specific reference site to drawing a ‘guiding image’ (Woolsey et al., 2007) based on historical data and imagery, as well as mathematical models, to guide setting the restoration objectives. A similar principle is applied in the EU Water Framework Directive (2000/60/EC) where it acknowledges unrealistic attempts to set a “near-natural reference” of river ecological conditions; rather, using systems that are “less-damaged” than the restoration system is recommended (Hughes et al., 2008).
c. Defining timeframe to measure success
Measuring the success of restoration objectives often requires many years of data. In addition, determining the appropriate time periods over which monitoring should be conducted is difficult to predict (Taylor, 2002). Although the scientific community acknowledges that there still is “insufficient knowledge” on how fast biota responds to restoration (Hering et al., 2010), Weber practitioners should acknowledge this upfront and set milestones in the lifetime of the restoration project and monitor accordingly. While most scientific papers on restoration attach a timeframe to eco-hydrologic objectives, a considerable variation exists. This time variation should also be acknowledged by practitioners as shown in Table 1. Due to time and budget constraints, it is important to consider the timeline for achieving success, at least 15 years in the Weber case Table 1, when designing any restoration project, and not merely whether the targets are attained or not (Hering et al., 2010). This means setting milestones in the lifetime of the project and monitoring the passing of such milestones as incremental metrics towards achieving objectives. In addition, although some projects have measureable objectives, they may fail to report success if such objectives are not measured in the project timeframe.
d. Institutional Organization
Although river restoration projects are often triggered by a single federal or state agency, a community group, or a non-profit organization, they often serve multiple objectives for numerous stakeholders and have a larger positive impact. However, this creates an ownership problem between fragmented institutional stakeholders (Poff et al., 1997). Restoring the Weber River requires setting up a framework for managing the project post-construction. This institutional framework should include Ogden City in addition to federal agencies such as the Fish and Wildlife Service. This also ensures that monitoring is accounted for in the project budget.
4.3. Performing monitoring of the Weber Basin
Monitoring can range from a simple image comparison of the before and after restoration conditions to more complex approaches, such as measuring subtle changes in taxa richness, sediment loads, and migration mechanisms. Effective monitoring of the Weber requires integrating the monitoring and evaluation processes during the project planning stage (Fig. 4). The evaluation of the data collected in the monitoring process involves assessing three main parameters: appropriateness, effectiveness and efficiency. Appropriateness is a measure of how the pre-project objectives are set to address the problems at hand. Efficiency measures the extent to which the project inputs (time, money, resources, skills, etc.) were sufficient and suitable to deliver the project outputs. Effectiveness is an indicator that is used to assess whether project outcomes meet pre-project objectives, goals and expectations. Fig. 4 also shows that monitoring starts before the actual restoration activities begin and shows how monitoring fits in the overall picture of the project process. It also reflects how appropriateness, effectiveness and efficiency are realized as the project progresses.
In the Weber River, the restoration objectives of the WBWCD (2003) could be improved by incorporating other human-driven stressors and impacts discussed below. Weber restoration practitioners and researchers should first identify overarching problems, set objectives to address such problems and select appropriate and measurable indicators to measure success. Different literature, reports, and field observations suggest that human impacts on the Weber can be classified into four categories. These categories were the basis of the restoration objectives and indicators listed in (Table 1):
- Improving damaged riparian and lotic habitats and vegetation: grazing, agriculture, logging, littering (Fig. 5) and urbanization lead to loss of native species (buffalo, beaver, etc.), introduction of nonnative species (cheatgrass, knapweeds, rainbow trout, etc.) and reduction in cover or change in plant community composition.
- Restoring stream flow modifications: this includes altered channel shape and dimensions, and flow hydraulics, fragmented habitat, reduced floodplain connectivity, and fish barriers. Flow alteration to agricultural purposes is the major stream flow problem in the Weber as shown in (Fig. 5). This leads to low flow problems especially in summer months which is a major concern to fish population and fish groups (e.g. Trout unlimited). This also has serious impacts on the habitat connectivity and the ability of fish to migrate and spawn.
- Enhancing impaired water quality: nutrient enrichment, sediment loading, organic materials, and temperature are the major water quality problems in the Weber. Agricultural activities contribute to nearly 22% of the problem and urban activities (point and nonpoint sources) contribute to over 40% (UDWQ, 2005). This leads to instability of stream-banks, increased runoff and transport of contaminants, and degradation of groundwater quality.
- Restoring physically altered channel geomorphology: incised channels, elimination of vegetative cover (mining, highways, development, railroads, etc.), displacement of aquatic and riparian habitat and materials (e.g. canalization, levee construction, gravel mining, and access trails) all have altered the geomorphology of the channel along the Weber.
Figure 5. Examples of human impacts on the Weber River and riparian area. Right: example of littering on the Weber streambank. Cars and trash line many of the banks in Morgan Diversion of the Weber River. Those items have increased the degraded long-term loss of geomorphic function and habitat quality. Left: example of flow alteration for agricultural purpose. A large levee is built at the Morgan Diversion of the Weber River leading to fragmentation of the watershed, fish habitat barrier, and increase of sedimentation problem upstream.
Accordingly, indicators, spatial and temporal scales along with uncertainties and risks can be identified as shown in Table 1. Monitoring sites in the Weber should be fixed and connected to a network of data gauges to report changes in hydrologic indicators and reveal what type of restoration is needed, when and where across the watershed.
Table 1. Restoration needs, objectives, and indicator matrix – Weber River Basin (Summers 1996; Downs & Kondolf 2002; Perrow & Davy 2002; Woolsey et al. 2007; Pinto et al. 2009; Poff et al. 2010; Friberg et al. 2011, author)
5. Conclusion and Recommendations for practitioners
Although many authors call for the need to develop comprehensive and inclusive standards for monitoring the success of restoration projects, the high variability and uniqueness of river and riparian restoration projects suggest otherwise. Defining success is imperative to the values and priorities of the project stakeholders. Therefore, a global set of standards may not be applicable or even desirable given the available resources and the stakeholders’ values. Hence, a more site-specific customized monitoring program would be more suitable to the Weber Basin case. Measuring success in the Weber requires both short- and long-term monitoring of the success indicators and evaluation of the path to attain expected outcomes. Monitoring should be integrated in the design of restoration projects and the uncertainty of the results and the project outcomes should be understood in order to better guide decision-making. Uncertainty in the monitoring process can either be caused by the inherent natural variability or by our fundamental lack of knowledge to model natural systems.
Weber River Basin restoration efforts should revisit the 2003 Watershed Restoration Action Strategy, learn from the small-scale Ogden River restoration project and incorporate the other ecological and hydrological problems of the basin. Accordingly, the following guidelines are recommended as best practices to improve the quality and effectiveness of the project:
- Setting clear objectives based on the problems identified and the desired conditions in the ‘guiding image’. Objectives should be measurable and time-bound. Indicators of measurements, as well as their temporal and spatial scales should be clearly spelled out in formulating the project objectives.
- ‘Success’ is not the best descriptive term to evaluate restoration projects. Using the well-defined terms of ‘appropriateness’, ‘efficiency’, and ‘effectiveness’ to describe monitoring and evaluation process outcomes will significantly help communicating results with project planners and improve adaptive management.
- Planning for a cooperative, adaptive monitoring process and appraisal along the project timeframe to assess the success of restoration efforts. Monitoring can range from a simple process of imagery comparison to time-series data analysis. Available resources (budget, time, manpower, etc.) should be planned accordingly and/or additional support should be sought.
- Project design, monitoring data and plans and as-built surveys need to documented and archived, preferably electronically, so that retrieval of information for the long-term monitoring and appraisal can be effective and meaningful.
- Uncertainties and risks should be anticipated and identified at the early stages of the project and a prescription for action (or no action) to be taken if the project fails to meet its indicators of success.
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