Complete quantitative outputs from stormwater, financial, MCDA, Monte Carlo, adversarial, and environmental models
SCS Curve Number runoff for 7 development scenarios across 5 design storms. The model uses SSURGO-calibrated soil data with 17 soil map units (30 components). Dominant Hydrologic Soil Group: B (64.0% of site area).
SSURGO-calibrated SCS-CN method (TR-55). Curve numbers computed from land cover mix per scenario. Dual HSG soils (B/D, A/D) use undrained (worse) group for conservative estimates. Forest CN from TR-55 Table 2-2c (woods, good condition). Open space CN from TR-55 Table 2-2a (good condition, >75% grass). Impervious CN = 98 (paved surfaces, roofs). Design storms from NOAA Atlas 14 for Asheville, NC region. Helene-scale based on observed 13.98 inches from Hurricane Helene (Sept 2024).
| Scenario | Description | CN | % Cleared | % Impervious |
|---|---|---|---|---|
| A | Stadium + Housing | 85.3 | 85% | 65% |
| A2 | Stadium Only | 76.7 | 56% | 44% |
| C | Heavy Housing | 81.6 | 78% | 55% |
| C2 | Medium Housing | 72.7 | 51% | 33% |
| D | Light Housing + Park | 66.0 | 22% | 18% |
| B/J | Full Preservation / Research Forest | 58.7 | 0% | 0% |
| Scenario | 2-yr 24hr (3.5") |
10-yr 24hr (5.2") |
25-yr 24hr (6.1") |
100-yr 24hr (7.0") |
Helene-scale (13.98") |
|---|---|---|---|---|---|
| A Stadium + Housing | 2,493,677 | 4,378,757 | 5,412,120 | 6,459,744 | 14,792,053 |
| A2 Stadium Only | 1,723,874 | 3,377,523 | 4,321,346 | 5,294,931 | 13,315,466 |
| C Heavy Housing | 2,141,774 | 3,934,748 | 4,933,486 | 5,952,875 | 14,169,942 |
| C2 Medium Housing | 1,419,714 | 2,948,062 | 3,840,185 | 4,769,664 | 12,590,966 |
| D Light Housing + Park | 977,943 | 2,279,224 | 3,072,642 | 3,915,640 | 11,320,403 |
| B Full Preservation | 586,299 | 1,623,332 | 2,294,435 | 3,026,635 | 9,850,775 |
| J Research Forest | 586,299 | 1,623,332 | 2,294,435 | 3,026,635 | 9,850,775 |
Scenario A (Stadium + Housing) produces 14.8 million gallons of runoff in a Helene-scale event — 4.9 million gallons more than the baseline forest (B/J at 9.9M gallons). That is a 50% increase in stormwater volume from clearing 85% of the canopy.
Even the 2-year storm produces 4.3x more runoff under Scenario A than under preservation.
30-year NPV analysis separated into three perspectives: Public (taxpayers), University (UNCA), and Developer. The original -$132M figure conflated all three perspectives. This corrected model isolates who pays and who benefits.
The original -$132M was the developer's cost, not the public cost. The actual public cost is the $29M subsidy + ~$15M infrastructure = ~$44M. The developer bears the $204M construction cost as a business risk. These are fundamentally different financial exposures.
| Scenario | Public NPV @5% | University NPV @5% | Developer NPV @5% |
|---|---|---|---|
| A Stadium (AECOM) | -$46.0M | +$18.6M | -$149.5M |
| E-H Housing Swap | +$43.3M | +$15.5M | +$14.7M |
| H1 Hybrid | +$32.3M | +$21.4M | +$14.7M |
| B No Action | +$10.6M | $0 | $0 |
| J Research Forest | +$11.3M | +$24.2M | $0 |
Public perspective: The stadium (A) is the only scenario with negative public NPV. Every alternative generates $10M–$43M in positive public value over 30 years.
University perspective: Research Forest (J) actually generates the highest university NPV (+$24.2M) through grants, field station fees, and endowment. The stadium generates +$18.6M but carries extreme risk.
Developer perspective: The stadium is a -$149.5M loss for the developer. Housing swap scenarios generate +$14.7M — the only profitable development path.
Multi-Criteria Decision Analysis across 21 objectives with equal weighting. Course of Action (COA) analysis with Pareto dominance testing and robustness assessment.
| Rank | Scenario | Description | Score | Pareto | Recommendation |
|---|---|---|---|---|---|
| 1 | H | Forest Preserved; No Stadium; Housing MC + City | 92.4 | Dominant | PROCEED |
| 2 | E | Forest as Park; Stadium 53 Birch; Housing MC | 84.0 | Dominant | PROCEED |
| 3 | F | Forest Preserved; Stadium Brevard Rd; Housing MC | 84.0 | Dominant | PROCEED |
| 4 | I | No Stadium; Forest Preserved; Non-RE Revenue | 83.7 | Dominant | PROCEED |
| 5 | G | Forest Preserved; Stadium South Slope; Housing MC | 83.2 | Dominated | CONSIDER |
| 6 | J | Research Forest (Living Laboratory) | 80.7 | Dominant | CONSIDER |
| 7 | B | Full Forest Preservation | 72.0 | Dominated | CONSIDER |
| 8 | D | Light Housing + Community Park | 61.0 | Dominated | ELIMINATE |
| 9 | C2 | Medium Housing + Buffers | 43.4 | Dominant | ELIMINATE |
| 10 | C | Heavy Housing on Forest | 35.4 | Dominant | ELIMINATE |
| 11 | A2 | Stadium Only on Forest | 21.2 | Dominated | ELIMINATE |
| 12 | A | Stadium + Housing on Forest (AECOM) | 17.0 | Dominated | ELIMINATE |
PROCEED: Robust (top-3 under ALL weight schemes) or top-5 and non-dominated.
CONSIDER: Partially dominated or mid-ranking; merits further analysis.
ELIMINATE: Dominated by 4+ scenarios or consistently bottom-ranked.
Pareto front: C, C2, E, F, H, I, J are all non-dominated on at least one objective combination. However, Scenario A is dominated by 9 of 11 other scenarios — every other option outperforms it on multiple objectives simultaneously.
1,000 random weight draws (uniform distribution across 20 objectives) to test whether the ranking is sensitive to how you weight the criteria. It is not.
| Scenario | Wins | Win Rate | Interpretation |
|---|---|---|---|
| H Forest Preserved; Housing MC + City | 1,000 | 100.0% | Wins under every possible weight combination tested |
| All other scenarios (A, A2, B, C, C2, D, E, F, G, I, J) | 0 | 0.0% | Never ranked first under any weight draw |
Even at 95% financial weight (treating the decision as almost entirely about money), Scenario A cannot enter the top 6. Its structural disadvantages — zero tax revenue (tax-exempt), $29M public subsidy, irreversible forest clearing — create a deficit that no weight combination can overcome.
Minimax regret measures worst-case disappointment: "What is the maximum I could regret choosing this scenario?"
| Scenario | Max Regret (pts) | Interpretation |
|---|---|---|
| H1 Hybrid | 16 | Lowest regret — safest choice regardless of priorities |
| H Forest Preserved; Housing MC + City | 16 | Tied for safest choice |
| E | 17 | Near-minimal regret |
| F | 17 | Near-minimal regret |
| I | 17 | Near-minimal regret |
| ... intermediate scenarios omitted ... | ||
| A Stadium on Forest | 100 | Maximum possible regret — worst choice under any weighting |
| A2 Stadium Only | 100 | Maximum possible regret |
The regret analysis is unambiguous: H/H1 have a maximum regret of 16 points (you can never be very wrong choosing them), while A has a regret of 100 points (you could be maximally wrong choosing it).
The adversarial test gives Scenario A the developer's best case: maximum plausible scores on every qualitative objective while keeping model-derived scores (stormwater, financial, reversibility) locked. Does H still win?
52 score adjustments favoring development scenarios. Model-locked objectives (stormwater, tax revenue, public subsidy, reversibility, floodway compliance) cannot be changed because they are derived from physical or financial models, not opinion.
| Weight Scheme | Original Gap | Adversarial Gap | Reduction | H Still #1? |
|---|---|---|---|---|
| Equal | 78.2 | 51.4 | -34% | Yes (H #1, A #11) |
| Environmental | 80.4 | 59.6 | -26% | Yes (H #1, A #12) |
| Financial | 74.1 | 47.3 | -36% | Yes (H #1, A #11) |
| Equity | 78.0 | 46.3 | -41% | Yes (H #1, A #11) |
| Governance | 81.9 | 53.2 | -35% | Yes (H #1, A #12) |
| Resilience | 79.6 | 54.5 | -32% | Yes (H #1, A #12) |
| Floodway | 81.9 | 57.4 | -30% | Yes (H #1, A #12) |
H wins under all 7 weight schemes in both original and adversarial scoring. The gap narrows from ~78 to ~40–60 points but never closes. Even giving A a score of 100 on every qualitative objective, H still wins under most weight schemes. The structural handicap of zero tax revenue, $29M public subsidy, and 85% irreversible clearing is uncloseable.
To flip the result, you would need to change physical reality (make the stadium taxable) or add entirely new objectives (e.g., "athletic prestige") weighted heavily enough to overcome the structural gap.
Habitat fragmentation, urban heat island, and carbon stock models for each development scenario. Data from Hansen Global Forest Change (30m), Asheville block group HVI, and Appalachian forest carbon literature.
| Scenario | Cleared (ac) | Forest Retained | Core Habitat (ac) | Narrowest Corridor | Edge:Area Ratio |
|---|---|---|---|---|---|
| A Stadium + Housing | 34.9 | 15% | 1.87 | 60 m | 0.34 |
| C Heavy Housing | 31.0 | 22% | 5.45 | 30 m | 0.31 |
| A2 Stadium Only | 22.3 | 44% | 3.11 | 30 m | 0.28 |
| C2 Medium Housing | 20.2 | 49% | 11.68 | 30 m | 0.31 |
| D Light Development | 7.8 | 78% | 38.46 | 180 m | 0.20 |
| B/J Preservation | 0.0 | 100% | 47.34 | 480 m | 0.17 |
| Scenario | Temp. Increase | Trees Preserved | Cooling NPV (30yr) | HVI Change |
|---|---|---|---|---|
| A Stadium + Housing | +1.98°C (+3.57°F) | 675 | $92,612 | +137% |
| C Heavy Housing | +1.82°C (+3.27°F) | 989 | $135,831 | +126% |
| A2 Stadium Only | +1.31°C (+2.35°F) | 1,979 | $271,662 | +90% |
| C2 Medium Housing | +1.19°C (+2.14°F) | 2,205 | $302,533 | +82% |
| D Light Development | +0.51°C (+0.92°F) | 3,510 | $481,583 | +35% |
| B/J Preservation | 0.0°C | 4,500 | $617,414 | -0.3% |
| Scenario | CO2 Released (Mg) | Social Cost of Release | CO2 Preserved (Mg) | Yrs to Recapture |
|---|---|---|---|---|
| A Stadium + Housing | 8,673 | $442,347 | 1,913 | 43.7 |
| C Heavy Housing | 7,959 | $405,918 | 2,806 | 43.7 |
| A2 Stadium Only | 5,714 | $291,429 | 5,612 | 43.7 |
| C2 Medium Housing | 5,204 | $265,408 | 6,250 | 43.7 |
| D Light Development | 2,245 | $114,490 | 9,949 | 43.7 |
| B/J Preservation | 0 | $0 | 12,755 | 0 |
Total forest carbon stock: 3,478 MgC (12,755 Mg CO2 equivalent). Scenario A releases 8,673 Mg CO2 with a social cost of $442,347 (at EPA IWG 2024 rate of $51/ton). It would take 43.7 years of regrowth to recapture the released carbon. Annual sequestration preserved under full forest: 27.3 MgC/yr ($5,109/yr value, $100,133 NPV over 30 years).
All models use publicly available data. No proprietary data was used in any analysis.
| Source | Description | Use |
|---|---|---|
| USDA SSURGO | Soil Survey Geographic Database — 17 soil map units, 30 components with hydrologic soil groups | Stormwater curve number calibration |
| NOAA Atlas 14 | Precipitation Frequency Data Server — 2yr through 100yr design storms for Asheville, NC | Design storm precipitation depths |
| Hurricane Helene Observations | Observed 13.98 inches rainfall during Sept 2024 event | Extreme storm scenario |
| SCS TR-55 | Urban Hydrology for Small Watersheds — curve number tables for forest, open space, impervious | Runoff computation method |
| FEMA Flood Maps | National Flood Insurance Program maps — SFHA, floodway delineation | Flood risk assessment, floodway compliance scoring |
| Buncombe County Parcels | County GIS parcel boundaries with ownership, acreage, tax data (134,436 parcels) | Alternative site scoring, public land inventory |
| Hansen GFC v1.12 | Global Forest Change — 30m treecover2000 dataset | Forest canopy mapping, fragmentation analysis |
| Asheville HVI Data | Block group Heat Vulnerability Index from urban_heat.geojson | Urban heat island modeling, HVI projection |
| Jenkins et al. 2001 | Appalachian oak-hickory carbon stocks (biomass equations) | Forest carbon stock estimation |
| Smith et al. 2006 | Forest regrowth rates for Appalachian hardwoods | Carbon recapture timeline |
| Ziter et al. 2019 | Urban canopy cooling effects — 0.075°C per 1% canopy | Temperature increase modeling |
| Nowak & Greenfield 2018 | Urban tree cooling economics — $7/tree/year cooling benefit | Monetary value of cooling services |
| US EPA IWG 2024 | Interagency Working Group Social Cost of Carbon — $51/ton CO2 | Monetizing carbon release and sequestration |
| USFS Forest Valuation | Ecosystem services valued at $10K/acre/yr for urban forests | 30-year NPV of forest services |
| Buncombe County Tax Office | Multifamily assessment rates — $83K/acre/yr | Housing tax revenue projections |
| AECOM Proposal | $204M construction cost, 25,000-seat stadium, P3 structure | Scenario A baseline costs |
| Esri Living Atlas LULC | 10m land use/land cover timeseries (2017–2023) | Historical canopy change validation |