Economic Impact Statistics
| Statistic | Value | Source |
|---|---|---|
| Annual combined cost of invasive aquatic plants in the U.S. | $10B+ (incl. ecosystem-service losses) | Pimentel et al. (2005) |
| Annual direct U.S. aquatic-weed control spending | $100M+ (industry estimate) | Rockwell (2003); AERF |
| Property-value impact of severe weed infestation on lakefront homes | Up to 16% reduction (regional studies) | Peer-reviewed studies (e.g., Halstead et al. 2003) |
| California Delta aquatic-weed program annual budget | $10M+ (recent years) | CA Division of Boating and Waterways |
| Florida statewide aquatic-plant management program | $30M+/year (recent years) | Florida Fish and Wildlife Conservation Commission |
Biological & Ecological Statistics
| Statistic | Value | Species / Context |
|---|---|---|
| Peak growth rate | Up to 1 in/day | Hydrilla (under optimal light, nutrients, temperature) |
| Biomass doubling time | 6–18 days | Water hyacinth |
| Biomass doubling time | 2–3 days | Duckweed (Lemna minor) |
| Tubers per square meter (dense stand) | 5,000+ | Hydrilla |
| Tuber sediment viability | Up to 7 years | Hydrilla |
| Daily dissolved-oxygen swing (dense weeds) | 6+ mg/L between dawn and afternoon | Submerged-weed-dominated lakes |
| Fish-kill DO threshold | <2 mg/L sustained | Most warmwater sportfish |
Distribution & Management Statistics
| Statistic | Value | Source |
|---|---|---|
| Non-native aquatic plant species established in U.S. waters | 200+ | USGS NAS database |
| U.S. states with established hydrilla | 30+ | USGS NAS |
| U.S. states with established Eurasian watermilfoil | 45+ | USGS NAS |
| Typical chemical treatment cost (aquatic herbicide) | $200–$600/acre | U.S. industry averages |
| Typical mechanical harvesting cost | $500–$1,500/acre | U.S. industry averages |
| Permit type required for most U.S. aquatic herbicide use | NPDES Pesticide General Permit + state license | U.S. EPA |
How to Cite These Statistics
Where a primary source is given in the right-most column above, please cite the primary source and (optionally) AquaticWeed.org as the secondary reference. Example:
"Hydrilla can grow up to one inch per day (USGS NAS database; via AquaticWeed.org)."
Related Resources on AquaticWeed.org
Ten-Year Lake Management Plan: Lake Wingra, WI
Lake Wingra, a 342-acre urban lake in Madison, WI, developed a comprehensive 10-year management plan coordinating the City of Madison, University of Wisconsin, and adjacent neighborhood associations. The plan addressed Eurasian watermilfoil, curly-leaf pondweed, and purple loosestrife through an integrated approach including targeted herbicide treatment, mechanical harvesting, native plant restoration, and public education.
Key outcome: The structured multi-agency planning process secured consistent funding across multiple budget cycles, a key advantage over ad hoc management. Native plant restoration efforts showed measurable progress in designated restoration zones within three years of initiation.
- U.S. Geological Survey — Nonindigenous Aquatic Species Database https://nas.er.usgs.gov/
- U.S. Army Corps of Engineers — Aquatic Plant Information System (APIS) https://apis.erdc.dren.mil/
- USDA APHIS — Federal Noxious Weed List https://www.aphis.usda.gov/plant-pests-diseases/weeds/noxious
- U.S. EPA — Aquatic Pesticide Use & NPDES Permits https://www.epa.gov/npdes/pesticide-permitting
- Pimentel et al. (2005) — Update on environmental and economic costs of invasive species in the U.S., Ecological Economics 52(3): 273–288. https://www.sciencedirect.com/science/article/abs/pii/S0921800904003027
- Rockwell, H.W. (2003) — Summary of a Survey of the Literature on the Economic Impact of Aquatic Weeds, Aquatic Ecosystem Restoration Foundation. https://www.aquatics.org/publications.html
We used the integrated management framework from this site to structure our Eurasian watermilfoil control program. After three seasons we've reduced lake-wide coverage by 78% on our 340-acre water body.
Susan Thibodeau Lake District Manager, MN · Crow Wing CountyThe seasonal timing guidance has been invaluable. Treating at the right growth stage cut our herbicide costs by nearly 30% without sacrificing efficacy on our county-managed reservoir.
Dale Buchanan County Parks Director, MI · Kalamazoo County