{"id":1462,"date":"2016-05-06T23:03:17","date_gmt":"2016-05-06T23:03:17","guid":{"rendered":"http:\/\/elmontgomery.com\/?p=1190"},"modified":"2022-12-07T14:44:19","modified_gmt":"2022-12-07T21:44:19","slug":"quantifying-final-ecosystem-service-values-santa-cruz-river-example-build","status":"publish","type":"post","link":"https:\/\/elmontgomery.com\/es\/hydro-notes\/quantifying-final-ecosystem-service-values-santa-cruz-river-example-build\/","title":{"rendered":"Cuantificaci\u00f3n de valores de servicios ecosist\u00e9micos \u201cfinales\u201d: un ejemplo del r\u00edo Santa Cruz para construir"},"content":{"rendered":"

If you don\u2019t live in the Tucson area, odds are you\u2019ve never heard of the Santa Cruz River. Locals know it as a normally dry channel alongside a pleasant bike path that occasionally swells after a decent monsoon. Yet there is far more to this river\u2019s story.<\/p>\n

This fascinating waterway has reaches harboring habitats that depend on both perennial flow and near-surface groundwater. The Santa Cruz is binational; its headwaters in extreme southern Arizona loop briefly through Sonora, Mexico, and then head north\/northwest, intersecting Tucson. Much of Tucson\u2019s early history revolves around the river, and historically perennial flows were found near \u201cA\u201d Mountain.<\/p>\n

Today, two lengthy reaches of perennial flow are sustained by continuous releases of treated effluent. These reaches are located in northwest Tucson at Roger and Ina Roads, and at the international treatment facility in Rio Rico near Green Valley. Somewhat accidentally, riparian habitats have sprung up in these areas, including rare cottonwood-willow gallery forest, and associated bird life. The river has even begun supporting small fish<\/a>.<\/p>\n

Future river conditions depend on a number of factors, including the Arizona state laws controlling recharge. Currently, the state offers only a 50 percent credit for in-channel recharge, in contrast to a 100 percent credit for off-channel recharge \u2014 a lack of incentive that could reduce the amount of water available for instream habitat. Mexico\u2019s actions also influence the upper Santa Cruz; it owns most of the effluent affecting the southern reach and recently began diverting more of this effluent to its own treatment facility<\/a> for its own use rather than allowing it to flow north. <\/span><\/p>\n

To proactively plan for the river\u2019s future, we will need to quantify the value of various environmental management outcomes.<\/p>\n

Some Background: Ecosystem Services & Non-Use Values<\/h2>\n

A concept fundamental to valuing the outcome of an environmental management option is \u201cecosystem services,\u201d a term that refers to the benefits humans receive from the environment or wildlife. Some of these benefits are biophysical in nature \u2014 for example, improvements to water quality that affect human health. However, it is also important to account for the way people feel<\/em> about an ecosystem service. For example, some people may care strongly about preserving rare, instream habitats; others may not. To quantify the full suite of river-related services, social science is typically necessary.<\/p>\n

Among the most challenging ecosystem service values to quantify are \u201cnon-use\u201d values, which tell us that environmental outcomes can matter to people even if they do not use the resource<\/em>. Classic examples include public support for endangered species or other rare environmental resources. Non-use values can be critical to capturing the costs and benefits affecting all stakeholders of a given environmental management decision.<\/p>\n

Study Methodology & Results<\/h2>\n

The Santa Cruz River was recently the subject of a series of federally funded studies on ecosystem services. One EPA study quantified the river attributes that were of greatest interest to the public based on painstakingly collected feedback from over 100 persons in one-on-one interviews and numerous focus groups[1]<\/a>. This study showed that, across various sociodemographics, southern Arizona residents valued visible the surface water, mature vegetation, and fish and wildlife associated with rivers. These preferences were overwhelming.<\/p>\n

A follow-up study sought to quantify the extent of these preferences using a survey that hypothesized a variety of future river scenarios. Developed to capture both use and non-use values, the survey was deployed after extensive pretesting via interviews and focus groups. It allowed each respondent to state his or her \u201cwillingness to pay\u201d for the following measures:<\/p>\n