Memorandum

City of Lawrence

Utilities Department

TO:	David L. Corliss – City Manager Cynthia Wagner - Assistant City Manager Diane Stoddard - Assistant City Manager
FROM:	Dave Wagner – Director of Utilities
CC:	Philip Ciesielski, - Asst. Director of Utilities Jeanette Klamm, Utilities Programs Manager Mike Lawless – Asst. Director of Utilities Scott McCullough – Director of Planning and Development Services
Date:	March 7, 2013
RE:	Wastewater Capacity in Relation to Population

During previous discussions of wastewater plant capacity, the Commission has posed questions regarding the relationship of the city’s population to the available capacity of the current wastewater treatment plant.

The resolution and final population numbers for Lawrence for the 2010 U.S. Census do not appreciably change estimates of remaining organic wastewater treatment capacity. This is because “remaining capacity” is determined based on actual, measured, organic loading values. “Remaining capacity” is not dependent on actual population.

Staff’s recommendation for expanded capacity allocates organic load on a per capita basis. If the actual population is less than the estimates used, the loading value per capita would be actually somewhat higher. This means that on a population basis we could accommodate less growth than the larger population estimate. However, these numbers do not vary our analysis to a significant amount.

It is critical to appreciate that the Master Plan recommendation on proceeding with the Wakarusa Wastewater treatment plant is based on three items, which have not been altered by the recent U.S. Census finding:  1)   our existing facility has wet weather capacity issues currently; 2) our existing collection transmission facilities are inadequate along the critical 31^st Street corridor during wet weather; and 3) our organic load capacity is diminishing.

Please let us know if you have further questions or need additional information.