Potential Economic Benefits to Santa Ana River Watershed of Forest Restoration. Barbara Wyse, Senior Economist

Transcription

1 Potential Economic Benefits to Santa Ana River Watershed of Forest Restoration Barbara Wyse, Senior Economist July 25, 2012

2 Presentation Overview Purpose / Motivation for Study Scope Approach FINDINGS! Uncertainty and Interpretation

3 Purpose Are funding forest restoration measures in the Santa Ana River Watershed s economic interest? t? 1. What is the connection between forest restoration and Santa Ana watershed water supply/water quality? 2. What are the types/magnitude of economic benefit of restoration measures? 3. What is the level of certainty regarding economic benefit findings? 4. What are the data gaps/next steps that can increase certainty?

4 Motivation for Study Findings Elsewhere Santa Fe Municipal Watershed, NM Forest restoration projects to reduce fire risk, increase water quality Customers pay an average monthly fee of $0.54 Denver Water, CO >$10 million costs to Denver Water due to 138,000 FS acres burned (>1 million cubic yards sediment in water supply reservoir) $33 million over 5 years for forest treatment/watershed protection Charles River, MA Millions of dollars in damages and hundreds of deaths in floods $8.3 million in land acquisition, same benefits as $100 million dam/levees Catskill / Delaware Watershed, NY City of New York was out of compliance with EPA water quality standards $1.5 billion over 10 years to protect the watershed and upgrade infrastructure Avoided $6 billion in capital and $300 million in operating costs

5 Parallels for Santa Ana River Watershed 1. Forest Service Watershed with high risk of fire a. Costs of sedimentation in recharge ponds / river channel - Reduced water supply - Increased O&M Costs 2. Supply limited water basin a. Potential high costs of reduced recharge/streamflow - Purchase of additional imported water - Potential ti shortages 3. Flash flow water supply a. Potential high costs of flooding - Costs to water suppliers/flood control agencies/others - Reduced groundwater recharge

6 Scope of Analysis Restoration Measures Thinning, Road Retrofitting, Meadow Restoration, Chaparral Restoration Water Supply Effects on Santa Ana River Watershed Quantity/Quality Economic Benefits to Santa Ana River Watershed Recharge Basin Maintenance Costs, Water Purchase Costs

7 Approach 1. Focus on thinning restoration benefits a. Fire risk reduction b. Water supply enhancement 2. Gather data a. What have others found? b. What data is available for San Bernardino/Cleveland NF? c. What are supply/quality y costs facing Santa Ana River Watershed that may be affected by thinning? 3. Define ranges for potential water supply benefits 4. Model expected $ benefits and level of certainty

8 Data Sources 1. Case Studies 2. Scientific Literature (15+ studies on watershed restoration/forest management and hydrology) 3. US Forest Service Data and Publications 4. Interviews with Districts (7 districts/flood control agencies) a. Bob Tincher, San Bernardino Valley MWD b. Dave Schroeder, Chino Basin Water CD c. Erin Morales, Cucamonga Valley WD d. Greg Woodside, Orange County WD e. Jack Nelson, Yucaipa Valley WD f. James McKenzie, San Bernardino County Flood Control g. Mark Tettemer, Irvine Ranch WD

9 Thinning Benefits Model Overview 2 Types of Benefits, 2 Models 1. Forest fuel reduction increased streamflow (thru reduced ET) 2. Forest fuel reduction reduced sediment / debris flows (thru reduced catastrophic fire risk) Model Steps 1. Literature on ranges of effects to expect 2. Local Data on San Bernardino/Cleveland NF and streamflow data 3. Define Range of Effects / Benefits for Santa Ana River Watershed

10 Step 1: Thinning Effects Literature on Water Quantity Forest fuel reduction increased streamflow, BUT Magnitude difficult to quantify Large ranges from studies Most studies find large volume removal is necessary Drainage Area Watershed % watershed treated MAP MAF Increase in Flow % change flow hectares acres Aspect Slope Vegetation Beaver Creek, AZ 100% % 124 W 21% Utah juniper pinyon forest Beaver Creek, AZ 83% % 146 W 7% Utah juniper pinyon forest Beaver Creek, AZ 100% % 42 SW 5% alligator and Utah Junipir ponderosa pine forest Beaver Creek, AZ 100% % 184 SW 7% ponderosa pine, gambel oak, alligator juniper Beaver Creek, AZ 33% % 452 W 6% ponderosa pine, gambel oak, alligator juniper Castle Creek, AZ 100% % 364 SE ponderosa pine Coyote Creek, OR 50% % 69 NE 23 36% Doug fir, mixed conifer Coyote Creek, OR 30% % 68 NE 23 36% Doug fir, mixed conifer Coyote Creek, OR 100% % 50 NE 23 36% Doug fir, mixed conifer Deadhorse Creek, CO 35% % 41 S 40% old growth lodgepole pine Entiat, WA 100% % 514 SE Ponderosa pine and Doug fir Entiat, WA 100% % 563 Ponderosa pine and Doug fir Entiat, WA 100% % 473 Ponderosa pine and Doug fir Fox Creek, OR 25% % 59 WNW 5 9% PacificSilverfir, fir, overmature western Hemlock and Doug fir Fox Creek, OR 25% % 71 W 5 9% Doug fir, western Hemlock Frazer, CO 40% % 289 N 77% subalpine forest (lodgepole pine, spruce fir): 23% alpine forest Source: Numerous sources, summarized in Marvin, Sarah, Possible Changes in Water Yield and Peak Flows in Response to Forest Management

11 Step 1 (cont): Economic Value of Water Quantity Big Range of Value from Difference Sources Avoided cost of purchasing alternative water Multiple sources of water $ / AF State Water Project Water Metropolitan Water District Cost of Shortages Cost to residential consumers of water supply restrictions Up to $2,000/AF in reduced value

12 Step 1 (cont): Identify Most Likely Values for Santa Ana River Watershed from Literature Define Range and Distribution of Water Supply Effects 25% reduction in density is needed before any increase in stream flow can be measured. For every 1% reduction in tree stand density (> 25%), a mean of 0.6% in water flow effects, with 10 th percentile at 0.5% and 90 th percentile at 0.8% Define Range and Distribution of Per Unit Water Value (Delivered Cost) $75 - $450 /AF based on cost of SWP and MWD imported water Combine Distribution of Water Supply Effects and Per Unit Water Values Risk Model) Provides best possible information on most likely effects, within context of the possible range of effects

13 Step 2: Gather Required Local Data What is the reduction in forest volume that would result from thinning? i What is the current stand density in San Bernardino/Cleveland NF watersheds? What is the target stand density in the watersheds? What is the current acreage of forest that requires thinning to reach target density? What is the current streamflow volume in Santa Ana River Watershed areas?

14 Step 2 (cont): Local Data on Acreage to Thin Target density = 150 trees / acre Minimum density for thinning: 200 trees/acre Source: USDA Forest Service

15 Step 2 (cont): Local Data on Streamflow Case Study: San Bernardino Valley Water District Sub Basin Data Precipitation is assumed to be held constant at average historic rates Timing of flows was not considered, only average annual flow volumes Creek Sub Basin Acreage Base Flow (AFY) Lytle 29,654 33,612 Cajon Creek 36,201 8,825 Devil Canyon 3,530 1,959 East Twin Creek 5,579 3,887 City Creek NR Highland 12,487 8,512 Mill Creek Yucaipa 27,172 27,733733

16 Step 3, Results: Range of Effects / Benefits A - Lytle ( ) / Annual Benefits $19,371 $49, % 90.0% 5.0% 90% chance that thinning subbasin gives $19 - $50,000 annual benefits Values x 10^ A - Lytle ( ) / Annual Benefits Minimum $15, Maximum $65, Mean $32, Std Dev $9, Values 1000 $40- $100 per acre thinned $15,000 0 $20,000 0 $25,000 0 $30,000 0 $35,000 0 $40,000 0 $45,000 0 $50,000 0 $55,000 0 $60,000 0 $65,000 0 $70, acres have a stand density greater than 200 trees per acre and would be thinned

17 Results (cont): Water Supply Benefits from Thinning i 1, acres Select Tributaries Acres Thinned Supply Annual Annual Annual Impact Benefits Benefits Benefits (AFY) (min, 10%) (mean) (max, 90%) A Lytle $19,268 $32,400 $50,070 B Cajon C $905 $1,520 $2,351 C Devil Cyn 49 9 $810 $1,360 $2,106 D E Twin C 28 7 $663 $1,120 $1,724 E City C NR Highland $1,947 $3,270 $5,059 H Mill C Yucaipa $12,645 $21,270 $32,861 90% chance of $35- $95,000 annual benefits with mean of $60,000 90% chance of $31- $82 annual benefits per acre thinned, with mean of $53 per acre thinned If thin every 20 years, with same benefits, most likely present value is ~$800/acre Total 1, $36,238 $60,940 $94,171

18 Thinning Model 2: Effects on Fire Risk and Sediment Loads Forest fuel reduction reduced fire risk reduced sediment BUT fire risk reduction difficult to quantify Reduced sediment difficult to quantify Some studies find large volume removal is necessary Fire events can result in erosion and heavy sediment loads in waterways if followed by storm events. Sediment can build in recharge basins, clogging them and reducing or eliminating percolation of water into the groundwater table. Sediment removal costs $10-$15 per cubic yard

19 Steps 1 and 2: Thinning and Fire/Sediment Risk Reduction in Santa Ana River Watershed Fire Level Baseline Thinned Risk Sediment Loads # Recharge Reduction (cubic yards) Basins Affected Magnitude I 3.8 % (26 yr) % 100 1,000 2 Magnitude II 3.6 % (28 yr) % 1,000 10, Magnitude III 6.3 % (16 yr) % 10, Data Sources USGS Data on Post-fire Debris-Flows in San Gabriel Mountains Fire Risk Reduction from Literature Review, interviews with USFS

20 Step 2: Reduced Sediment from Thinning Santa Ana Watershed Values x 10^ Annual Sediment Reduction 3,935 20, % 90.0% 5.0% 90% chance that thinning Santa Ana watershed would result in 4,000 20,000 cubic yards sediment (annual average) Sediment Reduction Minimum 2, Maximum 34, Mean 10, Std Dev 5, Values , , , , , , ,000 Most Likely 10,000 cubic yards reduced sediment (annual average) Reduction in sediment removal, expressed in cubic yards

21 Step 3: Avoided Sedimentation Costs of Thinning Most Likely Savings: $186,000 annually Most Likely Savings per acre thinned: $50, or ~$800 present value 90% chance that thinning watershed would save $47,000 to $0.4 million annually

22 Conclusions and Interpretation: Benefits of Thinning Expected annual value per acre thinned in Santa Ana River watershed: $100 per acre, if all 3,800 acres thinned, approximately $3.8 million in annual value Present value, assuming 20 year thinning cycle, of ~$1500 per acre thinned 2 Primary, Quantifiable Water Supply Benefits Increased streamflow $50/Acre 90% chance $31-$82 $82 per acre thinned Key assumption: All streamflow results in increased recharge and availability to Santa Ana River Watershed Decreased sediment, $50/Acre 90% chance $12-$115 $115 per acre thinned Key assumption: All sediment results in sediment removal costs Key Uncertainties: Percent of watershed thinned Locations of effect Magnitude of ecological response

23 Benefits of Road Retrofitting Road Retrofitting Reduced sedimentation, BUT Magnitude difficult to quantify, depends on many road and watershed characteristics The potential reduction in sediment yields available from road mitigation in large basins has not been quantified. (Goode, et al, 2012) Per mile of road, literature indicates Sediment loads in WA State average 2 tons/year/mile of road Road retrofitting may reduce sediment 50-90%, if ditches are vegetated Value of road retrofitting is most likely $23/year/mile, range of $7-49 Present Value is $197, range of $54-$454 Assuming 1-8 tons per mile, most likely l value of 1.9 tons per mile Assuming life of road retrofitting project of 5 25 years

24 Thank You! Barbara Wyse Cardno ENTRIX Phone: