Infrastructure Database Development for Snoqualmie Pass Utility District

Snoqualmie Pass sits in the Cascade Range at an elevation of 3015 feet, straddling the Kittitas and King counties and bisected by the important I-90 interstate. The district provides water and sewer services to over 560 homes in the area. With no existing GIS or digital asset management system in place and knowledgeable staff retiring, the district was concerned about losing its institutional knowledge. To ensure this information was maintained and the district could adequately identify and manage its assets in a difficult alpine environment, they asked FLO to build a GIS asset database from scratch. It was especially important to capture accurate location points for their water and sewer assets, as utility assets are often completely buried by the area’s heavy snowfall and ice in the winter. Having to dig down in the right place to find a water valve under several feet of snow was common and difficult to do when nearby features were also covered. 

Before going into the field to collect data, the FLO project team completed extensive historical research and data preparation to inform our field collection. The district and FLO collaborated to develop an efficient and safe data collection route and identify priority asset areas. A data schema for attribution of collected points was developed based on standard Esri data structures commonly used by local governments. Now, when the district works with other government entities or contractors, their data is in a familiar and compatible format.

With initial project planning and research complete and a data structure ready, FLO GIS technicians headed to the field, using the latest GPS technology to cost-effectively capture asset points down to 3-inch accuracy. We used ArcGIS Online and Trimble Collector software hosted on iPads for basemaps, planning, and verification and for uploading data to show to the client at the end of each day. 

Processing data collected in the field included:

• Differentially correcting the data for the desired level of accuracy
• Transferring GPS points and relevant attributes to the district’s new data schemas
• Connecting surface points to create water and sewer lines, including flow direction
• Performing geometry checks on data
• Developing unique identifiers for all features

With data processing complete, we created a web map and application hosted in the district’s new ArcGIS Online environment so they can easily view, use, manage, and update their new GIS system in the office or the field. Staff can use the map, GPS units, or even their device to find assets more easily. As part of our ongoing support with the district, we have provided GPS data capture training, responsive data updates, and new datasets to track key features and work, including repairs and leaks.