ABSTRACT:

The Measurement and Infrastructure Gap Analysis in Utah's Sevier River Basin consisted of a comprehensive inventory and evaluation of existing diversion and stream measurement infrastructure along 30 subsystems with 4 distribution systems: the Upper Sevier River, Lower Sevier River, Upper San Pitch River, Lower San Pitch River. The primary objective of this “Gap Analysis” was to develop methods to identify and rank areas throughout the Sevier River Basin where new or updated measurement infrastructure is needed to serve water rights holders. A ranking analysis combined existing measurement infrastructure gaps and potential spatial gaps to create a ranked list of potential new and updates to current measurement infrastructure. Stakeholder feedback was solicited and used to create a stakeholder identified needs list.

In total, we documented 147 existing measurement stations in the Sever River basin along selected subsystems. This included 88 diversion and 59 streamgaging stations. Of these 147 existing stations, 34 diversion stations and 16 streamgages were found to be in need of updates to the existing infrastructure. Stations in need of measurement infrastructure updates were concentrated in the Upper San Pitch distribution system.

Stakeholders identified 73 proposed locations for new stations and 55 existing stations in need of infrastructure updates. The majority of requests were concentrated in the Upper Sevier distribution system, which accounted for 53 proposed new stations and 17 requests for updates to existing infrastructure. The Lower Sevier distribution system had 5 requests for new stations and 10 requests for infrastructure updates. In the Upper San Pitch distribution system, stakeholders identified 7 potential new station locations and 19 existing stations requiring updates, while the Lower San Pitch distribution system had 8 requests for new stations and 9 requests for updates to existing infrastructure.

In addition to the stakeholder identified needs for new stations and updates to existing, USU completed an independent analysis of where future investment should be targeted. For example, the analysis identified gaging the San Pitch at its confluence with the Sevier River as critical to accounting in the basin, as well as making updates to stations on the mainstem of the San Pitch to better account for gains and losses as water moves through the system. These findings reflected the priorities identified by water rights holders and by state WRi engineers.