Valuing instream-related services of wastewater

- Strong support documented for preserving effluent-dominated river services.
- Surprising mixed support for water quality safe for full body contact.
- Values appear to be more ecologically-based than recreationally motivated.
- Evidence for sensitivity of value to river reach quality and city of residence.
- Generalized mixed logit outperformed basic and mixed logit models.

In the southwestern US water resources are increasingly scarce, leaving perennial habitats and associated environmental amenities vulnerable to off-channel water demands. To provide management insight, the value of two instream flow related ecosystem services are estimated for two river reaches, for two separate population centers. The specific services are preservation of instream flow extent and accompanying Cottonwood-Willow riparian forest, and improving water quality to be safe for full body recreational contact. The case study is of a highly modified effluent-dominated waterway, yet strong support for maintaining wet river habitat was documented, apparently due mainly to ecological rather than recreational motivations. In general, the more distant river reach with more trees was more highly valued on a per mile basis, and the population center closest to both river reaches more highly valued their preservation. Support was mixed for increasing water treatment to allow safe full body contact. Well-known multinomial and mixed logit models are compared with a relatively new generalized mixed logit framework, with the latter performing best. Documentation of public values associated with the posed river management options assist decision-making for the case study and similar contexts lacking quantification of the value of instream flow related ecosystem services.