Project Information

Project Purpose

The objective of this study is to address the feasibility of drywells for LID stormwater management in Flagstaff. The Fourth Street area was designed decades ago with little consideration for stormwater management given a growing urban area. As such, the CAL Ranch site, located on the southeast corner of Fourth Street and 7th Avenue, is evaluated in this feasibility study, as requested by the client, Mr. Douglas Slover, City of Flagstaff Stormwater Engineer. Currently, the CAL Ranch site has no LID stormwater management features. The site is being evaluated as a theoretical new development, with the assumption that the site is undeveloped and in a natural state. The developed state assumes the current condition of the site, where stormwater management facilities (drywell, retention basin, stormwater routing structures) will be incorporated for best management and LID practices in accordance with the COF stormwater design manual.

A drywell is a vertical retention system which allows excess storm runoff to infiltrate into the ground. Drywells allow runoff to collect in an underground chamber filled and lined with highly-permeable materials. Drywells commonly implement pretreatment systems to improve water quality. This pretreatment typically includes a sedimentation chamber to prevent sediment buildup within the drywell, which prolongs the lifespan of the drywell by decreasing the suspended solids of water entering the drywell, thus decreasing maintenance costs.

Site Locations

CAL Ranch site is located north of 7th Avenue between Fourth Street and King Street. Half of the adjacent easements were considered as part of the site for on-site stormwater calculations. The area of the CAL Ranch site and half of the adjacent easements is 9.39 acres. North of the CAL Ranch is a UPS store and various other small businesses with lots that are 100% impermeable. The site sits at a mean elevation of 6883 feet above sea level.

CAL Ranch Site Map with 1’ Elevation Contours
C-A-L Ranch Site Location
North Fourth St.

For our project code research, the following manual was used:

  • Maricopa County’s Drainage Policies and Standards
  • Buckeye Public Works Department
  • Coconino County Code and Ordinances
  • Arizona Department of Environmental Quality Code

Staffing and Budget


The estimated number of hours for each role in this project are presented in the staffing file, which is distributed based on the listed tasks.


The budget file contains the estimated cost from completing this project.

Tasks and Schedule


This project contains multiple tasks that were set to complete the project on time and with all the data and results.


The schedule was built based on the estimated time that will be spent on each task in order to finish the project on the right time and before the due date!