This study uses contingent valuation to determine consumer’s willingness-to-pay (WTP) for reducing hydrilla in two alternative spring-fed river systems in Northwest Florida - the Wacissa River (an open access park) and the Wakulla Springs (a gated park). Two dissimilar payment vehicles -gate and power bill fees- are used to assess the economic value of reducing the density of this aquatic weed. A total sample of 317 recreational users was used to estimate their WTP for a 50% reduction in the density of hydrilla. Our results show a favorable response from consumers to pay for a hydrilla reduction program. Specifically, at Wakulla Springs, the average WTP is $1.63 for monthly power bill surcharge and $3.76 for per trip gate fee. Conversely, at the Wacissa River the average WTP is $1.49 power bill surcharge. This study also analyzes the determinants affecting consumer’s WTP. Our results show that respondents who are from the local surrounding area are more likely to participate and pay a program to reduce hydrilla. In addition, the amenities available in the park also influence consumer’s WTP. Policy implications stemming from these results are also discussed.