The Botanist

Project description

The project site is a surface parking lot that was part of WillowWood Office Plaza, identified on parcel 47-4-02-02-002A1. The existing structure referenced in project documents is a 5-story brick building of 24,408 square feet. The proposed development, known as The Botanist, consists of 260 total multifamily rental units in a 7-story building (with a special exception requested for 81 feet of height), approximately 5,000 square feet of ground-floor retail, and a gross site area of ±129,130 square feet (±2.96 acres). The project is described in the June 21, 2024 Statement of Support as "development of multifamily rental housing consistent with the SAP recommendations." The project status is listed as Under Construction in the City of Fairfax project directory as of July 2026.

The unit count has evolved through the application process: the original December 2022 submission proposed 270 units, an August 2023 submission proposed 268 units, and the controlling June 2024 proffers and General Development Plan fix the maximum at 260 units. Affordable unit count and total parking spaces are noted in project documents but are not carried as confirmed spec values in this analysis and are not used in any computation here.

Economic effects

New demand. The project is estimated to generate 234 to 252 new households (computed as proposed units multiplied by an occupancy rate assumption of 0.90–0.97), yielding a central estimate of 247 households. Applying Rutgers CUPR bedroom-mix multipliers for persons per multifamily unit (range 1.5–2.2, central 1.8), the estimated new resident population is 351 to 555, with a central estimate of approximately 445.

Spending and cluster capture. New resident spending is estimated across six categories using BLS Consumer Expenditure Survey 2023 data, scaled by household count and an income premium for new-construction multifamily (range 1.0–1.25, central 1.125), with each category adjusted by an Engel-curve elasticity. The method multiplies households by the CES category spend and applies an income-ratio elasticity factor. The largest estimated annual spending pools are comparison retail ($1,716,000–$3,092,000), grocery ($1,520,000–$2,451,000), entertainment ($1,432,000–$2,639,000), and restaurants and bars ($1,360,000–$2,397,000).

Where that spending lands is estimated using a Huff model that treats every retail point of interest as an individual destination and applies a joint destination-and-mode choice — these are screening estimates, not predictions. The model ranks where new spending is likely to go and is sensitive to the walk-decay parameter (β = 0.05–0.15 per minute) and the zero-impedance walk-preference assumptions. The top-ranked clusters by modeled annual capture are:

• Fairchester Drive & Hill Street: $1,945,000–$3,721,000 (central $2,742,000), drawing across grocery, restaurants, comparison retail, convenience retail, personal services, and entertainment
• Chain Bridge Road & North Street: $876,000–$1,757,000 (central $1,231,000), with notable entertainment and restaurant components
• Fair Lakes Parkway & Fair Oaks Mall: $618,000–$965,000 (central $839,000), dominated by comparison retail and entertainment
• Blenheim Boulevard & Fairfax Boulevard: $416,000–$728,000 (central $555,000)
• Mathy Drive & Pickett Road: $323,000–$484,000 (central $423,000)

The Huff model also estimates an in-city capture share for all retail of 0.57–0.64 (central 0.59) and for food-away-from-home of 0.61–0.71 (central 0.64), meaning a material share of spending is projected to leave the city boundary regardless of the project.

Project's own ground-floor retail. The 5,000 square feet of on-site retail competes as a destination in the Huff model, with its attractiveness converted to a POI-equivalent using an assumed 2,000 square feet per equivalent POI (range 1,500–3,000). The modeled annual capture at the project's own retail is estimated at $11,000–$28,000 (central $20,000) — this is a screening estimate. Of that, the portion arriving on foot is estimated at $3,500–$19,000 (central $10,000).

Foot-traffic index. The foot-traffic index change across the 10 nearest commercial street segments is estimated at 0.1% (relative index). This figure is computed by allocating exact marginal trip flows from the site — using POI-weighted destinations, an exponential walk-decay function, and shortest-path routing — against a sampled betweenness index of today's pedestrian population. This is a screening estimate; the baseline is a sampled index, not calibrated pedestrian counts.

Jobs ledger. The existing 24,408 square feet of commercial space implies 49 to 98 displaced jobs (central estimate approximately 70), computed by dividing existing commercial square footage by an assumed square footage per office job of 250–500 (central 350). The proposed 5,000 square feet of ground-floor retail implies 7 to 13 new on-site retail jobs (central 10), computed by dividing proposed retail square footage by an assumed 400–700 square feet per retail job (central 500). The net on-site job change is estimated at −36 to −90 (central approximately −60), reflecting the conversion from commercial office use to predominantly residential with a small retail component. No new office space is proposed, so office jobs added is zero.

Fiscal effects

Current tax. The current real estate tax on parcel 47-4-02-02-002A1 is $69,246 per year, computed as the current assessed value multiplied by the city real estate tax rate, drawn from the City of Fairfax Real Estate Assessment Database (Patriot WebPro, 2026) and the FY2027 adopted rate.

Projected assessed value and real estate tax. The projected assessed value is estimated at $94,496,000–$121,322,000 (central $95,230,000), computed as: units multiplied by an assessed value per unit derived from three City of Fairfax apartment-class comparables built since 2011 (central $360,983/unit, range $359,599–$458,932/unit), plus retail square footage multiplied by an assumed commercial value per square foot of $200–$400 (central $275). No office space is proposed, so that component is zero. This yields a projected real estate tax of $1,013,000–$1,301,000 per year (central $1,021,000), and a real estate tax increase of $944,000–$1,232,000 per year (central $952,000) after removing the current site tax.

Other recurring revenues. Additional revenue lines estimated in this analysis are:

• Personal property tax on resident vehicles (rough estimate): $87,000–$375,000 per year (central $200,000), computed as new households multiplied by assumed vehicles per household (1.0–1.8, central 1.4) and assumed average vehicle assessed value ($9,000–$20,000, central $14,000), at the city personal property tax rate. This is a rough estimate; no project-specific vehicle data exist.
• BPOL business license tax on project retail (rough estimate, net-new): $369–$2,980 per year (central $1,188). Computed as proposed retail square footage multiplied by assumed gross sales per square foot ($250–$600, central $400), the BPOL retail rate, and a net-new share assumption (0.15–0.50, central 0.30) to account for displacement of receipts from existing city businesses.
• Business tangible property tax (rough estimate): $826–$3,097 per year (central $1,652), computed as proposed commercial square footage multiplied by an assumed equipment value per square foot ($4–$15, central $8) at the city personal property rate.
• Meals tax on captured in-city dining: $37,000–$77,000 per year (central $54,000), computed using restaurant spending multiplied by the in-city capture share from the Huff model and the city meals tax rate.
• Meals tax on the project's own restaurants (rough estimate, net-new): $2,000–$47,000 per year (central $13,000).
• Local sales tax share on captured in-city retail: $20,000–$39,000 per year (central $28,000), computed as in-city captured retail spending multiplied by the local sales tax share under Virginia Code § 58.1-605.
• Local sales tax on project's own retail (rough estimate, net-new): $1,844–$14,898 per year (central $5,939).

Service costs. Two cost methods are employed in this analysis; both are described here.

The marginal framing method estimates non-school per-capita costs at the city average (drawn from the FY2027 adopted General Fund budget: non-school expenditures of $207,912,496 minus $76,429,791 in school-related spending, divided by 25,026 residents, yielding $5,254 per capita), then applies a marginal cost factor of 0.25–0.55 (central 0.35) on the grounds that fixed-overhead services do not scale linearly with infill residents. School costs are estimated separately as the number of students multiplied by the net local cost per pupil of $19,961 (derived from FY2027 tuition contract: $76,429,791 minus $14,492,271 in state education revenue, divided by 3,103 students). The estimated number of K-12 students from the project is 13–31 (central 21), computed as 260 units multiplied by an assumed 0.05–0.12 students per unit (central 0.08), based on high-rise multifamily generation rates. Under the marginal framing, total annual service cost is estimated at $721,000–$2,226,000 (central $1,233,000), of which the school component is approximately $259,000–$623,000 (central $415,000).

The marginal framing understates costs if the influx of new residents triggers a discrete service-capacity expansion; the marginal cost factor's range (0.25–0.55) is intended to carry that uncertainty. A full average-cost framing (dividing total city expenditures by current population and applying the result without reduction) would yield higher cost estimates; the reader should note that the marginal framing is deliberately more favorable to new development than the average-cost alternative, and the two methods can differ substantially.

Net fiscal impact. Under the marginal framing, the net annual fiscal impact of this analysis is estimated at −$1,132,000 to +$1,070,000 (central approximately +$23,000), computed as incremental new recurring revenues minus marginal service costs. The wide range reflects compounded uncertainty across the residential value per unit, the marginal cost factor, the occupancy rate, the average household size, and the students-per-unit assumption.

Comparison with city staff estimates. Three city staff reports — the July 9, 2024 City Council Public Hearing Agenda Cover Memo, the July 9, 2024 City Council Staff Report, and the April 22, 2024 Planning Commission Staff Report — each state, as published: "Staff estimates that this proposal would bring a net fiscal benefit of between −$250,000 and +$306,000 annually with an average of $56,000." These figures are reported here as published and are not combined with or averaged into the estimates above.

The city staff range of −$250,000 to +$306,000 and this analysis's range of −$1,132,000 to +$1,070,000 overlap: both include outcomes near zero and both include a negative scenario. However, this analysis's range is substantially wider in both directions. The most visible methodological reasons for the difference are: (1) this analysis applies a marginal cost factor of 0.25–0.55 to non-school per-capita costs, and at the high end of that factor the cost estimate rises well above the staff range; (2) this analysis includes a rough-estimate personal property tax line ($87,000–$375,000) that, at its high end, expands the revenue side beyond the staff range; and (3) the student generation assumption (0.05–0.12 per unit) and the resulting school cost ($259,000–$623,000) vary more widely than the staff model appears to allow. The staff methodology is not fully reproduced in available documents, so additional differences may exist that are not visible in the metric methods and notes.

Not evaluated in this version

Several analytical components are deferred from this version of the report and were not computed. These include: a bike-lane corridor analysis, trail-connectivity and pedestrian-network evaluation, broader multimodal connectivity assessment, environmental and stormwater impact analysis, and a comparable-places study benchmarking The Botanist against similar mixed-use infill projects in comparable jurisdictions. These items are planned for future analysis versions and no results are presented here.