Memorandum

City of Lawrence

Utilities Department

TO:	Mary Miller
FROM:	Philip Ciesielski
CC:	Roger Coffey Dave Wagner Linda Finger
Date:	July 26, 2005
RE:	Sherylville Estates Sanitary Sewer Study – Utility Department Review Comments

The following comments summarize the results of the Utility Department’s review of the Sherylville Estates Sanitary Sewer Study completed by Charlie Steinbacher and submitted on July 15, 2005.  A scanned copy of the study is attached.

The proposed Sherylville Estates development encompasses approximately 5.63 acres in the sanitary sewer Kansas River-1 (KR-1) Drainage Basin. 

The proposed 19 residential single family lots, populated at 3.0 persons per lot, have the potential to generate sanitary sewer flows for a population of 57 persons.  According to the 2003 Wastewater Master Plan the total population equivalent increase in KR-1 from year 2000 to 2010 is 880 persons.  Within this context the proposed development is within the parameters of the 2003 Wastewater Master Plan.

The proposed Sherylville Estates development is situated northwest of, and flows to, the existing sanitary sewer Pump Station 28 (PS28) located at 505 Sandpiper Drive.  As currently configured PS28 does not have the capacity to accept the addition of the Sherylville Estates sewer flow.  The above referenced study addresses the limited capacity in PS28 by proposing to reroute the flow from PS35, located at 1206 Sunchase Drive, from a discharge point upstream of PS28 to a discharge point upstream of PS46, which is located east of the Riverside Business Park. 

After evaluating the study presented I will concur that there is available flow capacity in the gravity sanitary sewers upstream of PS46, and available pumping capacity at PS46 to accommodate the redirected PS35 discharge.  The redirection of the PS35 discharge from PS28 will allow PS28 to accommodate the Sherylville Estates sewerage flow.

There are, however, several things to keep in mind should the proposal move forward:

Most importantly for the purpose of this memo it is important to relay to the developer that the current study provides only a concept for the provision of sanitary sewer service and a verification of existing system capacity where required.  The acceptance of this study is not an acceptance of a design nor is it authorization to construct the proposed system modifications.  The developer will need to submit, for approval by the Department of Utilities, construction plans and specifications prepared by a qualified engineer which meet the Department’s standards and system requirements.

The redirection of the PS35 flow to the PS46 system does not comply with the recommendations of the 2003 Wastewater Master Plan.  Nor does it comply with the Department’s concept of sizing and constructing facilities to accommodate the flow generated by development within natural drainage basins.   

As proposed the redirection of the PS35 flows to PS46 is considered to be temporary.  PS46 was designed and constructed to handle sewerage flows from areas north of Riverridge Road.  The redirection of the PS35 flow utilizes approximately 12% of the available PS46 capacity.  Should the PS35 flows remain directed to PS46, PS46 would most likely require an upgrade to accommodate its entire service area.  Financial participation by the Sherylville Estates area in any capacity enhancements to PS46 that allow the PS35 flow to remain discharging to PS46 have not been defined.

The Department of Utilities has an interest in future projects to enhance, and possibly combine, the functions of PS28 and PS35.  This interest is driven by the identified capacity issue with PS28 as well as maintenance, operations, access and location issues with both pump stations.  Financial participation by the Sherylville Estates area in any capacity enhancements that allow the PS35 flow to be removed from PS46 has not been defined.