An economic assessment that monetizes the full range of financial, social, and environmental benefits associated with fire resilience projects provides water resource managers, elected officials, and other decision makers with important information about costs, benefits, and the return on investment from public expenditures. This information can be valuable for several reasons, including:

• Identifying engineered and nature-based infrastructure alternatives (and hybrid approaches) that maximize community value. Accounting for the full range of benefits associated with nature-based wildfire resilience projects and monetizing these benefits (when appropriate and feasible to do so) allows for an apples-to-apples comparison of benefits and costs. This helps practitioners and decision-makers understand the tradeoffs or complementarities associated with different types of infrastructure and to discern which approach (or combination of approaches) will yield the greatest value for their community.
• Building internal support for multi-benefit source water protection strategies. In some cases, utility staff or departments may not be familiar with the range or efficacy of wildfire risk interventions as alternatives to more traditional infrastructure projects (e.g., downstream treatment). Quantitative information on benefits can inform internal discussions during project development and planning
• Competing for scarce funding. In many areas, municipal departments must compete for funding with other important community Grant funds from external sources are also often subject to competitive proposal processes. Demonstrating the full value of proposed projects can make them more competitive, particularly if they help to achieve multiple community priorities.
• Leveraging alternative funding sources. Information on benefits can be used to leverage alternative funding streams from both public and private For example, information on public health and economic development benefits may leverage funding from public agencies that might not otherwise think about funding source water protection projects.
• Gaining support and buy-in from decision-makers and other stakeholders. Utilities and municipalities can use objective information on the benefits of wildfire resilience strategies to gain support from upper management and other key decision-makers and to communicate the value of proposed projects to stakeholders.

Ecosystem services are typically classified ecosystem services into four broad categories according to how they benefit people:

• Provisioning Services provide the physical materials that economies and communities use, such as fresh water, food, fiber, and other resources.
• Regulating Services are benefits obtained from ecosystem processes. Intact ecosystems provide regulation of climate, water quality/supply, and soil erosion and flood control. They also keep disease organisms in check.
• Supporting Services refer to the habitats which support food webs and all life on the planet, as well as natural functions (e.g., soil formation, nutrient cycling) that maintain ecosystem health and other ecosystem service types.
• Cultural services the non-material benefits that ecosystems provide to human societies and culture, including opportunities for recreation, tourism, aesthetic or artistic appreciation, and spirituality

TBL analysis follows the basic principles of what economists might refer to as a comprehensive and sound benefit-cost analysis – one that attempts to account for the full range of benefits and costs of a project or program over time. This includes benefits and costs borne “internally” by a municipality or agency, as well as those that are borne “externally” by other parties (e.g., households, businesses, special interest groups). The TBL approach provides an organizing framework within which the broad array of benefits (including ecosystem service benefits) and costs can be portrayed. It consists of:

1. A financial bottom line that reflects benefits that accrue directly to the utility, municipality, and/or the implementor of wildfire resilience projects in the form of cost savings.
2. A second bottom line to reflect social impacts of an agency action, or the benefits and costs that accrue directly to households and residents (e.g., improved health outcomes or enhanced recreation opportunities).
3. A third environmental bottom line that reflects direct environmental benefits (e.g., improved water quality, carbon emissions reduction and sequestration benefits).

The table below maps ecosystem services benefits of wildfire resilience interventions to relevant methods for valuing those benefits. Details about these valuation methods can be found in the following sections.

Stated preference methods rely on survey questions that ask individuals to make a choice, describe behavior, or state directly what they would be willing to pay for the non-market good or service being evaluated. Stated preference methods are based on the notion that there is some amount of market goods and services that people would be willing to trade off so they can benefit from a non-market good. This is often measured in terms of willingness to pay (WTP); stated preference studies typically yield average per-person or per-household WTP estimates for survey respondents. These estimates can be extrapolated to the wider study population to provide an indication of total non-market benefits or costs.

An advantage of stated preference methods is that they include the ability to estimate both use values and non-use values. For example, stated preference methods have been used to estimate WTP by recreationalists for water quality improvements that enhance water-based recreational activities (i.e., use values). They have also been used to estimate WTP for water quality improvements by individuals who do not necessarily participate in water-based recreation but who intrinsically value these improvements for the ecosystem or biodiversity benefits they provide (i.e., non-use values).

Revealed preference methods rely on choices people make in related markets to infer the value of a nonmarket good or service. Common revealed preference methods include hedonic pricing, travel cost, and averting behavior methods. Hedonic methods use statistical analysis to estimate the influence of different factors on observed market prices. For example, researchers have employed hedonic studies to infer the value of forest management activities that reduce fire risk by comparing differences in the price of properties that benefit from these treatments and those that do not. These studies use hedonic models to isolate the effect of these projects on a property’s market value while controlling for all other factors.

The travel cost method estimates WTP for recreation based on the choices people make to travel to a specific location. This method recognizes that users pay an implicit price by giving up time and money to recreate. Travel cost methods could be used to estimate how much more people are willing to pay to take recreational trips to areas that have better water quality or that have benefitted from stream restoration improvements.

The averting behavior method infers values from defensive or averting expenditures (e.g., expenditures made to avoid flood-related property damage or to reduce the potential for illness during extreme heat events). This method assumes that a person will continue to take protective action as long as the expected benefit exceeds the cost of doing so. It generates values that may be interpreted as lower bound estimates because averting expenditures only capture a portion of an individual’s WTP to avoid harm.

Avoided cost analysis determines the marginal cost of providing an equivalent service in another way. For example, reducing potential sediment loads to a water provider’s reservoir and delivery infrastructure can offset the cost to dredge, transport, and dispose of sediment and debris. Similarly, in areas where restoration projects can be used to reduce risk to water supply sources, this can offset (or delay) the need to draw upon or develop alternative sources of supply. When using avoided costs as a proxy for benefit values, analysts must carefully define a baseline scenario; this scenario must be consistently applied across all benefit categories. Avoided costs should only be used to measure benefits when they would actually be incurred in the absence of the planned restoration scenario.

Production function approaches value environmental goods and services based on their impact on production. They are based on the idea that environmental attributes can affect a sector’s production function, and that the effect on production can be valued at market prices. For example, high quality nature-based recreation sites can positively affect economic output associated with tourism.

Primary valuation studies (i.e., stated preference and revealed preference studies) typically require a significant amount of time, expertise, and financial resources. For this reason, researchers often use the benefits transfer approach to estimate non-market values. Benefits transfer is a secondary research approach that relies on estimates of existing economic values in one context to estimate economic values in a different context. There are numerous challenges and cautions to consider when using benefits transfer, however, when implemented correctly, with the recognition that the estimates are not intended to be precise, benefits transfer is accepted as a suitable method for estimating non-market benefits in various contexts. Benefits transfer is commonly used in economics, and there is a well-developed literature on how to correctly apply this method.

Defining a baseline scenario is a critical first step to conducting an economic analysis; it is often the key to revealing the benefits of a project or program. Establishing a baseline requires analysts to identify what would occur if the planned wildfire resilience projects were not implemented. For example, for water providers planning to implement projects that reduce the risk of post-fire reservoir sedimentation, the without-project baseline may include post-fire treatment, such as reservoir dredging, dredged material disposal, watershed slope stabilization, and energy (fossil fuel) consumption associated with these activities. For water providers who implement resilience projects to ensure water supply security, the without-project baseline should include consideration of alternative water supply sources and delivery infrastructure, and/or the cost of water supply disruptions.

An important aspect of defining the baseline is that it must reflect the future. The baseline is not the same thing as the “current” situation. Defining the baseline means looking into the years ahead. Since a plausible useful lifetime of wildfire resilience investments is 25 or more years, a matching long-term timeframe needs to be applied for the baseline and project scenario options. In the context of wildfire resilience, increased risk of wildfire associated with climate-change related weather patterns (e.g., drier and/or hotter conditions) is important to consider.

The baseline scenario has implications, and must be applied consistently, across benefits categories. There may also be a need to consider several aspects of the baseline scenario. For example, in some cases, communities may implement forest and watershed health projects to secure future outdoor recreation opportunities and to drive local economic activity based on recreation. Resilience projects may both protect existing uses, allow expansion of these uses, and/or facilitate the development of new recreation opportunities. The user needs to clearly articulate what would happen if wildfire eliminated these options.

Finally, in many cases, the benefits of wildfire resilience strategies depend on wildfire risk. Wildfire risk reflects:

1. the probability that a wildfire will occur; and
2. the consequences of a wildfire if it were to occur (this in turn is dependent on the severity of the wildfire event).

In establishing a baseline scenario for analysis, it is important to understand the current wildfire risk within a watershed. In subsequent steps, it will be important to identify how a potential wildfire resilience strategy will reduce the probability of a wildfire and/or its consequences.

A range of models and tools are available to help practitioners assess wildfire risk. Click here for high level review of several tools available for this purpose.

The next step is to establish a “with-project” scenario for evaluation and identify its associated benefits and outcomes. Different types of wildfire resilience projects result in different types and levels of benefits, as does the scale of implementation. Additional factors, such as study area topography, climate, recreational access, and other community characteristics also affect the types and level of benefits provided.

When identifying benefits, it is important to think about financial benefits that accrue directly to the utility or municipality, as well as environmental and social outcomes that benefit the broader community. Financial benefits to a utility may include costs associated with an alternative project that is avoided compared to the baseline. For example, a forest thinning project might avoid the need to replace a damaged water diversion system under the baseline scenario. Environmental benefits of wildfire resilience projects may include expanded or higher quality habitat and/or increased carbon storage. Social benefits may include enhanced recreational opportunities, flood risk reduction, public health improvements, and/or community economic development benefits, among others.

When compiling costs, it is important to think about the overall lifespan of the project, including initial design and construction costs and maintenance and replacement costs over time. If a subsidy or cost share is provided by an outside source (e.g., the state), these should be considered as part of the economic analysis. Any transaction costs and opportunity costs associated with the project should also be included.

Once all costs and benefits are identified, they can be evaluated to determine which must be qualitatively described (e.g., because quantification is not feasible), and which can and should be quantified. It may be useful to exclude benefits that have a large degree of uncertainty associated with them, are small and somewhat insignificant (i.e., they may not be worth quantifying), or that are politically or culturally sensitive. While it may not be possible to value these benefits, it may be useful to qualitatively characterize them.

The first step to valuing a benefit is to establish the physical quantities or outcomes associated with it. For wildfire resilience projects, these may include for example, tons of sediment transport avoided, pounds of air pollutants avoided, or the number of recreational user outings enabled by enhanced instream flows or water quality. These metrics serve as the initial step in the valuation process; it is therefore important to match the quantity units of measurement to whatever metric is available for the corresponding dollar values. Once the physical benefits have been estimated, a per unit dollar value often can be assigned to the benefit to reach a total value (quantity times per unit value). Monetary values can be estimated by applying the economic valuation methods described previously.

The table below presents common quantitative outcomes and economic analysis methods that can be used to value the benefits associated with wildfire resilience projects. While many can be valued using original studies, these benefits can also generally be estimated using benefits transfer techniques. For both physical outcomes and monetized benefits, ranges may be used (rather than a single point estimate) to better represent variability or uncertainty in the estimates. These outcomes should be evaluated under various assumptions related to fire severity.

In quantifying the value of fire resilience projects, it is important to account for the inherent uncertainty associated with wildfire risk. Specifically, the benefits of wildfire resilience projects are a function of burn probability, fire severity under pre- and post-project conditions (which in turn is a function of weather conditions, topography, point of ignition, and other factors, note that this only applies to strategies intended to reduce wildfire risk), and expected post fire outcomes with the planned interventions. Changes in assumptions related to these parameters provides for a reasonable range of benefit estimates. Click below to read a case study of how these factors were accounted for in a 2021 study that estimated the net economic benefits of Denver Water’s investments in proactive wildfire mitigation and source water protection under its Forests to Faucets (F2F) initiative.

It may not be feasible or desirable to express some types of benefits or costs in quantitative or monetary terms. However, it can be valuable to describe these non-quantified benefits and costs in a meaningful, qualitative manner. Benefits and costs may be described qualitatively, in part, by using a simple scale indicating the likely impact on net project benefits relative to the project benefits overall.

For example, impacts can be qualitatively ranked on a 5-point scale, ranging from -2 to +2, to reflect unquantified relative outcomes that span from very negative to very positive (e.g., a “-1” may signify an outcome with moderate unquantified costs, and a “+2” may represent a high unquantified benefit).  More complex or sophisticated rankings or methods, such as multi-criteria decision analysis, can also be applied. In any case, qualitative ratings should be accompanied by descriptions of the impact and should be explicitly carried through the analysis. Using participatory methods to ensure the opinions of relevant experts are included is especially important, such as wildlife biologists, water infrastructure engineers, or hydrology experts.

The benefits and costs of forest and watershed resilience projects occur as a stream of values that change over time. On the cost side, these may have large upfront capital costs, depending on the implementation schedule; in some cases, these costs may be spread over an amortization period. Benefits typically accrue over the life of project, and in the case of some benefit categories, continue to increase over time as vegetation becomes established and continues to grow. For example, Process Based Restoration techniques deliver benefits in a non-linear fashion as the water supply, groundwater recharge, habitat creation and sediment sequestration effects change as the project area natural system itself changes. As with costs, benefits will also vary based on the planned implementation schedule (e.g., as project elements or phases come online).

Values that occur in different time periods need to be adjusted to comparable “present values”. There are two interrelated factors to consider when comparing values from different times – inflation and the “time value of money.” When inflation is included in projecting values over time, the values are said to be in “nominal” terms. Many financial analyses are conducted in nominal dollars. However, for economic analyses, benefits and costs are normally not entered in nominal dollars. The use of “real” dollars (i.e., where no inflation rate is applied to future dollars so that all values are in the same dollar year) makes analyses easier and keeps inflation-related projections from clouding the analysis.

The “time value of money” captures a social preference for a dollar today over an inflation-adjusted dollar available in the future. The annual rate at which present values are preferred to deferred values is known as the discount rate (which is like an interest rate). The greater the preference for immediate benefits (time preference), or the greater expected rate of return on other investments today, the greater the discount rate. For fiscal year 2024, the discount rate for Federal water resources planning is 2.75%.

To compare streams of value over time from different projects, the stream of values for each project is discounted to “present value” using the discount rate. If both benefits and costs are involved, the present value of the costs is subtracted from the present value of the benefits to get the net present value (NPV) of the project.

Inherent in any high level economic analysis is some level of uncertainty. Uncertainties associated with estimated benefits and costs should be explicitly documented. The impact that these may have on the outcome of the analysis (e.g., in terms of their likelihood of increasing or decreasing net benefits, or an uncertain direction of change in net benefits) should be noted.

When it is possible with available data, ranges should be developed for an estimate by stating the upper and lower bounds. When bounding of an estimate is not possible, one can at least characterize uncertainty qualitatively by describing the sources of uncertainty and stating whether an estimate developed is likely to over- or under-estimate the true value.

In many cases it can be useful to explore the impact of uncertainties or key assumptions through sensitivity analysis. Sensitivity analysis involves systematically changing the value of a key input to see how it affects the outcome of the analysis. The change in results associated with a change in inputs can illuminate how important the impact of uncertainty in a particular variable is to the outcome. Sensitivity analysis is often performed by varying a particular input by equal amounts greater to and less than the current value. characterize uncertainty qualitatively by describing the sources of uncertainty and stating whether an estimate developed is likely to over- or under-estimate the true value.

Proper accounting of benefits is necessary to ensure against double counting. Benefits included in the analysis depend on the baseline established for the project. For example, if the baseline reflects a “do-nothing” scenario, and a project will address an erosion and sedimentation problem, then the sedimentation damages avoided by the project can be counted as a benefit. If the baseline includes an alternative (e.g., gray infrastructure) project that addresses the same sedimentation problem (and to the same extent), the benefits of the nature-based project can include either 1) the avoided costs of the alternative gray infrastructure project, or 2) the sedimentation damages avoided by the project. Including both would be double counting. The two alternatives can either be compared directly (e.g., by comparing flood risk reduction and other benefits of each alternative to their costs) or the avoided costs associated with the baseline project can be counted as a benefit of the nature-based solution being evaluated.

The economic value of forest resilience project benefits are often additive, meaning they can be added together to generate a total value. But some benefit categories are interconnected (and to some extent may overlap) and must be carefully evaluated to avoid double counting. One example relates to the habitat value that wildfire risk reduction strategies can provide. Habitat improvements are often measured based on willingness to pay (WTP) by households (sometimes within a specific distance) to expand or restore different habitat types. These values can vary based on whether recreational users (and uses) of the habitat are included in the estimates.

For example, for projects that improve instream habitat for fisheries, WTP estimates for individuals who fish may be higher than for non-recreational users because they are willing to pay for the non-use or intrinsic value they have for restoring habitat, as well as for the associated recreational benefits. Some stated preference study control for these variables to isolate use and non-use values. To avoid double counting it is important to understand the nature of WTP estimates before adding them to the value of separately calculated benefits, such as the value of recreational trips resulting from expanded or improved habitat.

A significant feature of a post-wildfire landscape is its increased erodibility from unstable slopes and soils. Fire retardants used to hamper wildfires also release pollutants that flow into water bodies. Potential impacts for water providers include sediment and pollutant flows into source waters and increased water treatment expenditures prior to delivery to retail customers. Treating highly turbid water can require additional filtration, energy use, and chemical inputs, and/or investments in new or expanded treatment infrastructure. Sometimes, high levels of turbidity post-fire can result in the shutdown of affected water treatment plants.

Wildfire resilience strategies designed to reduce the probability of a high severity fire event (i.e., pre-fire strategies such as thinning and prescribed burns) can mitigate these risks, thereby reducing the likelihood and magnitude of costs a water supplier might face to remove sediment, suspended solids, and other contaminants from the water it delivers. Other strategies, such as riparian and slope revegetation, stream restoration (e.g., in-stream structures, channel and headcut stabilization), and meadow restoration can reduce sediment transport and deposition after a fire does occur. These “post-fire” interventions do not mitigate risk or severity of wildfires but provide similar benefits to water suppliers because they serve to reduce sediment and pollutant loading to water treatment plants.

Check out the sections below for more information about the benefit outcomes from these investments, guidance on the information needed to assess benefits, resources for measuring those benefits, and a case study on avoided cost benefits from Greeley, Colorado.

Benefit Outcomes

An analysis of potential post-fire erosion, sediment, and pollutant flow risk can help to predict the costs that a water provider may incur to treat source water to a required or expected level of quality. These costs are “avoided costs” created by pre- and post-fire interventions; they represent quantifiable and monetizable financial benefits for water providers and the communities they serve.

In the event that fire-related water quality impairments result in a shutdown of water treatment plants, the avoided costs associated with water supply disruptions or for securing alternative water supplies can also be used to quantify the benefits of wildfire resilience projects (see section on enhanced water supply security).

Info Needed

For pre-fire interventions, it is important to consider how proposed strategies will reduce the probability and/or severity of wildfire compared to baseline conditions. Some studies report benefits as being conditional on fire occurring (e.g., assuming a fire occurs once over the life of a project), whereas others have taken an expected value approach that considers the probability of fires of different severity within a given year. It may also be useful to establish the risk of wildfire of sufficient severity to create highly erosive conditions within the subject area.

For both pre- and post-fire interventions, changes in landscape conditions following a fire must be modeled to predict changes in sedimentation and pollutant volumes/flows to relevant source waters. Outputs from fire behavior models can be input into erosion and sediment delivery / transport models to estimate these outcomes. Much of the information required to predict sedimentation volume and flow is geophysical, related to slopes, soil types, and precipitation patterns. Many models estimate erosion/sedimentation under various rainfall intensities and storm events (e.g., 5-, 10-, 100-year storms).

Sedimentation is often modeled as sediment load or volume delivered to a stream, so it is important to ensure this is converted to sediment load delivered to water supplies, and, as relevant, further converted to a change in total suspended solids or turbidity at a water treatment plant (WTP) intake point. Expected changes in sediment volume, turbidity, or other related water quality variables can then be tied to changes in water treatment costs (e.g., electricity, chemicals) based on local market estimates or historic expenditures by water suppliers.

Resources & How To

The FlamMap model, developed by the USDA Forest Service, can calculate fire behavior characteristics for a given landscape (e.g., spread rate, fire intensity, flame length, and major fire paths) within a spatial framework. Outputs can be used to estimate burn severity and likely erosion following a wildfire.

The Water Erosion Prediction Program and the InVEST Sediment Delivery Ratio Model are both erosion prediction models that can estimate avoided erosion impacts on aquatic ecosystems.

The Automated Geospatial Watershed Assessment (AGWA) is a geographic information system (GIS)-based tool that was developed by the USDA Forest Service to predict the potential impact of fire on runoff and erosion and to assess the watershed before and after a fire. The model incorporates two other models, the Soil and Water Assessment Tool (SWAT) and the KINematic Runoff and Erosion Model (KINEROS2) perform rapid, post-fire watershed assessments by using a burn severity map to modify existing land cover.

In Northern Colorado, the Peaks to People Water Fund’s Watershed Investment Tool uses regionally specific GIS and other data to model the effects of fuels reduction projects on erosion, sediment transport, and sediment removal costs. The Tool can be used to identify priority project areas or estimate the performance of individual projects.

Researchers at Utah State University are developing the Fire-Watershed Assessment Toolkit for Erosion and Routing (or Fire-WATER) that simulates post-wildfire erosion from both debris flow and hillslope processes and estimates sediment delivery to river channels. Fire-WATER combines the current USGS post-fire debris flow model, which predicts the probability of debris flow generation for all burned sub-catchments, with regional debris flow volume models and an updated debris flow sediment delivery model. Additionally, Fire-WATER simulates post-fire hillslope erosion by applying a post-fire version of the revised universal soil loss equation (RUSLE) and calculates sediment delivery to river channels. Collectively, the Fire-WATER components can all be run using publicly available datasets (at least for the western US), including but not limited to topography, rainfall intensity, soil erodibility, land cover, and wildfire soil burn severity.

Once the physical units are established, avoided water treatment costs can be estimated using historic data from water suppliers on related costs, ideally following wildfire events. Data from neighboring water suppliers can also be used if they have similar water supply infrastructure and treatment processes.

Some studies have estimated the cost elasticity of turbidity, or the response in WTP operation and maintenance costs to a change in turbidity levels. Cost elasticity estimates can be used as a good proxy where water suppliers do not have equations to estimate how a change in turbidity level impacts water treatment costs.

Case Study - Greeley, Colorado

The Peaks to People Water Fund has created a benefits valuation calculator that quantifies water quality and other benefits of forest and watershed restoration projects in Northern Colorado watersheds. Peaks to People seeks to connect watershed beneficiaries to strategic outcomes that can be achieved through restoration and fire risk reduction projects. The Fund’s Watershed Investment Tool enables the Fund and its partners to quantify the effectiveness of these projects while identifying project opportunities and associated budget needs.

Developed with assistance from the Colorado Forest Restoration Institute at Colorado State University, the Investment Tool is an optimization tool that links several existing model platforms (e.g., RUSLE, FlamMap 5.0, WEPP/GeoWEPP) to estimate the source water protection benefits of forest fuel reduction projects. The web version of the Tool provides illustrative outputs related to improvements in (or avoided risk to) water quality and avoided damages to private property, and geographically locates recommended projects that can attain desired outcomes within specified budget ranges.

The Tool allows water utilities to explore project benefits in both conditional (anticipated benefit given wildfire burns the treated area) and expected (anticipated benefit accounting for the probability the treated area is burned by wildfire) scenarios.

In the example illustrated above, a $1,000,000 investment in projects within the City of Greeley’s watershed would reduce erosion by over 70,000 metric tons in a post-fire scenario (if a fire were to occur), avoiding approximately $450,000 in water treatment costs.

Wildfires may pose direct risks to water supply infrastructure in the fire path, including intakes, conveyance infrastructure, pumphouses, or other structures that can be destroyed or damaged. Damage to pipes can compromise distribution systems, destroying assets and releasing contaminants into the water supply. Extensive damage to infrastructure can also result in water supply disruptions and/or the need for alternative supply sources.

Post-fire, water infrastructure may be susceptible to risks associated with the erosion from unstable soils, slopes, and fire-damaged forests. For example, increased sediments and debris in reservoirs from runoff and flash floods in burned areas can reduce reservoir capacity and effective service lifespan, or impair the operation of diversion structures or other equipment. Above ground flumes, aqueducts, and pipelines as well as intake structures can also be affected by increased sediment loading and debris.

Forest thinning, meadow restoration, and other projects that reduce the probability of a high severity fire event can reduce the likelihood that a water provider will incur costs to repair or replace damaged infrastructure. Post-fire restoration projects that stabilize slopes and soils and that remove hazard trees can similarly reduce the likelihood of infrastructure damage. Riparian and slope revegetation, in-stream structures (e.g., woody debris, logjams, etc.), channel and headcut stabilization, and meadow restoration are among the practices that can help to reduce runoff volumes and velocities in burned watersheds or stabilize vulnerable slopes.

Check out the sections below for more information about the benefit outcomes from these investments, guidance on the information needed to assess benefits, resources for measuring those benefits, and a case study on the benefits of Denver Water’s Forest to Faucets program.

Following wildfire events, debris flows and high sediment levels may threaten delivery infrastructure or create water quality conditions that inhibit water supply delivery. In such instances, it may be necessary for water providers to more heavily utilize back up supplies, arrange water transfers or exchanges with other water providers, or curtail water deliveries. Any of these options may create additional costs for the water provider and for retail water customers. Pre- and post-fire interventions that reduce the likelihood of debris flows, channel scouring, and hillside erosion are can contribute to water supply security by avoiding or reducing these impacts.

Pre-fire interventions, such as forest thinning and prescribed fire, and even invasive species removal (e.g., removal of tamarisk in California), can result in water supply/quantity benefits even if a fire does not occur. These so-called “no-regrets” actions can increase streamflow, recharge groundwater, and/or increase runoff to reservoirs and hydropower facilities. For example, in a 2015 study, researchers modelled the effect of ponderosa pine forest thinning in the Salt and Verde River watersheds on the reliability and cost of water supply to the Phoenix metropolitan area. They found that thinning (up to 50% of canopy cover) has the potential to increase annual water supply by 8%. This represented a net present value of surface water storage of $138 M (updated to 2024 USD), considering both water consumption and hydropower generation.

It is important to note that these projects do not always translate into a direct increase in water supplies because of water rights issues in some states. However, increases in stream flows and groundwater storage can support instream flow requirements and maintain hydropower revenues, and can offset the use of water supplies for these purposes.

Check out the sections below for more information about the benefit outcomes from these investments, guidance on the information needed to assess benefits, and resources for measuring those benefits.