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Mokelumne watershed avoided cost analysis: Why Sierra fuel treatments make economic sense

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A report prepared for the Sierra Nevada Conservancy, The Nature Conservancy, and US Department of Agriculture, Forest Service. Sierra Nevada Conservancy. Auburn, California.
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... Much of the forested land is at risk to wildfire as evidenced by the 2004 Power Fire (70 km 2 ) within the basin (Figure 1), and the nearby Rim (2013; 1,040 km 2 ) and King (2014; 390 km 2 ) fires. Major landowners include the U.S. Forest Service, Bureau of Land Management, and Sierra Pacific Industries (Buckley et al. 2014). ...
... In order to spatially prioritize fuel treatments and to determine the economic value of increasing treatments compared with a "do-nothing" scenario during this time of increasing fire threat, the U.S. Forest Service, The Sierra Nevada Conservancy, and The Nature Conservancy brought together a diverse set of stakeholders to form the Mokelumne Avoided Cost Analysis (MACA) committee (Buckley et al. 2014). Stakeholders included land, water and utilities managers, federal, state and local agencies, local stakeholders, and environmental organizations. ...
... Once calibrated, the model was run for 40,000 fire seasons. Additional details can be found in Buckley et al. (2014). ...
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Forests deliver a number of ecosystem services, including clean water. When forests are disturbed by wildfire, the timing and quantity of runoff can be altered, and the quality can be severely degraded. A modeling study for about 1500 km2 in the Upper Mokelumne River Watershed in California was conducted to determine the risk of wildfire and the associated potential sediment delivery should a wildfire occur, and to calculate the potential reduction in sediment delivery that might result from fuel reduction treatments. The first step was to predict wildfire severity and probability of occurrence under current vegetation conditions with FlamMap fire prediction tool. FlamMap uses current vegetation, topography, and wind characteristics to predict the speed, flame length, and direction of a simulated flame front for each 30-m pixel. As the first step in the erosion modeling, a geospatial interface for the WEPP model (GeoWEPP) was used to delineate approximately 6-ha hillslope polygons for the study area. The flame length values from FlamMap were then aggregated for each hillslope polygon to yield a predicted fire intensity. Fire intensity and pre-fire vegetation conditions were used to estimate fire severity (either unburned, low, moderate or high). The fire severity was combined with soil properties from the STATSGO database to build the vegetation and soil files needed to run WEPP for each polygon. Eight different stochastic climates were generated to account for the weather variability within the basin. A modified batching version of GeoWEPP was used to predict the first-year post-fire sediment yield from each hillslope and subwatershed. Estimated sediment yields ranged from 0 to more than 100 Mg/ha, and were typical of observed values. The polygons that generated the greatest amount of sediment or that were critical for reducing fire spread were identified, and these were "treated" by reducing the amount of fuel available for a wildfire. The erosion associated with these fuel treatments was estimated using WEPP. FlamMap and WEPP were run a second time to determine the extent to which the imposed treatments reduced fire intensity, fire severity, and the predicted sediment yields. The results allowed managers to quantify the net reduction in sediment delivery due to the prescribed treatments. The modeling also identified those polygons with the greatest net decline in sediment delivery, with the expectation that these polygons would have the highest priority for fuel reduction treatments. An economic value can be assigned to the predicted net change in sediment delivered to a reservoir or a specified decline in water quality. The estimated avoided costs due to the reduction in sediment delivery can help justify the optimized fuel treatments.
... Increased post-fire erosion rates can severely degrade water quality (Santín et al. 2015) and reduce reservoir storage capacity ( Tiedemann et al. 1979;Moody and Martin 2001;Neary et al. 2005;Smith et al. 2011;Santín et al. 2015). In response to these risks, land managers responsible for protecting forestlands and watersheds, espe- cially those that provide municipal water supplies, are consi- dering ways to mitigate the effects of wildfire on water resources through the use of fuel reduction treatments (Buckley et al. 2014;Sidman et al. 2015). Fuel reduction treatments, such as thinning and prescribed burning, have been shown to be effec- tive in modifying fire behaviour and fire severity (Reinhardt et al. 2008;Cochrane et al. 2012). ...
... The extensive forest stands within the basin are under both public and private ownership. Much of the forested land is at risk of wildfire as evidenced by the Power Fire (2004, 70 km 2 ) within the basin, and the nearby Rim (2013Rim ( , 1040 (Buckley et al. 2014). ...
... In order to spatially prioritise fuel treatments and to deter- mine the economic value of increasing treatments compared with a 'do-nothing' scenario during this time of increasing fire threat in the Upper Mokelumne Basin in California, the US Forest Service, The Sierra Nevada Conservancy and The Nature Conservancy brought together a diverse set of stakeholders to form the Mokelumne Avoided Cost Analysis (MACA) committee (Buckley et al. 2014). Stakeholders included land, water and utilities managers, federal, state and local agencies, local stake- holders, and environmental organisations. ...
... There were 16.2 miles of perennial streams, and 21.9 miles of seasonal streams affected, with the most intense effects in Beaver and East Panther Creeks. High postfire rates of soil erosion and sedimentation to streams were observed in the fire area (USDA 2005), and these can have an impact on water quality and reservoir capacity (Buckley et al. 2014). ...
... The nearest reservoirs with accumulated sediment data were Upper Bear River Reservoir (Spraberry 1964) in the northwest section of the Power study area, Tiger Creek Afterbay (Buckley et al. 2014), which intercepts all streams from the Power project plus Tiger Creek basin. Including all sediment sources (road surface, gullies, landslides, fill erosion) specific sediment delivery rate for the Power study area was 1.8 Mg km -2 yr -1 . ...
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... Partnering with farmers on working landscapes also contributes to the economic development of the surrounding region, which can help curb distress migration to cities. Quantifying these related benefits can lead to coalitions of support for investment and may even reveal benefits of equal or greater value than water quality. For example, a recent estimate of the cost avoidance associated with forest fuel treatment of 40,000 hectares in the Mokelumne Watershed-the source of drinking water for Oakland, California-found that the economic benefits of modeled forest fuel reduction treatments are two to three times the costs [27]. However, the broad diffusion of benefits would require a similarly diverse set of investors. ...
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Payments for watershed services (PWS) programs are becoming a popular governance approach in the western United States (US) to fund forest management aimed at source water protection. In this paper we conduct a cost-benefit analysis (CBA) of one of the first collaboratively funded PWS programs in the US, located in the municipal watersheds servicing Denver, Colorado. We combine wildfire modeling, sediment modeling, and primary and secondary data on economic values to quantify the impact of the program on protecting multiple values at risk. Our results show that while the program has led to diverse societal benefits, it is only economically efficient (benefit-cost ratio greater than one) when all co-benefits beyond source water protection are considered, and fuels treatments are assumed to encounter wildfire. When the probability of wildfire is accounted for, economic benefits would need to be triple what was estimated in our analysis to achieve economic efficiency. Our findings suggest that improving spatial prioritization of interventions would increase economic benefits and better data on treatment placement and costs would help facilitate future CBA of PWS programs focused on wildfire mitigation.
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