Bee Creek Sewer Trunk Line

for the City Council November 10, 2011

Background1997 WW Collection System Master Plan• Done by CDM Engineering• Identified Bee Creek Trunk Line as overloaded in wet weather

2004 Capital Improvement Plan StudyDone by CDM Engineering

Projected Low/Medium/Industrial density in Bee Creek sewer shed area

Determined entire BCTL would surcharge at Build-OutProposed Capital Plan up-sized BCTL from Plant to West side

Future Demands on the Bee Creek Trunk Line• New line must accommodate Urban density on west side

Wastewater Master Plan

Council approved Wastewater Master Plan in June 2011– What lines are near capacity, when must they be upgraded?– What lines need re-habilitation, and when?

Large investments required over next decadeBee Creek sewer trunk line built in 1973– West side developments were not anticipated 40 years ago– Plan to replace existing trunk line with a 48” trunk line

PROJECT DESCRIPTION START DESIGN BUILD ESTIMATED

COST

Bee Creek Trunk Line Phase I FY 11-12 FY-13 $9.3 M

Bee Creek Trunk Line Phase II FY 12-13 FY-14 $3.0 M

Bee Creek Sewer-shed Area

3 Flow Monitors

Results of Flow Monitoring

Monitor Locations > High School CSPD Hwy 6 & 2818

Full Flow Capacity(gallons per minute) 2,755 4,542 4,542

Fall 2011: Dry weather, with students here (gpm) 1,766 2,126 2,214

Total flow in a heavy rain event (adds 2,013 gpm) 3,799 4,139 4,227

Total flow with West Side units (adds 2,088 gpm) 5,887 6,227 6,315

Capacity of new Bee Creek Trunk Line (gpm) 20,000 20,000 20,000

Alternatives1. Replace Existing Trunk Line with 48” line

$14 million Lowest cost in capital and operational

2. Pump west side flow into adjacent sub-basin to the north

$20 million Moves flow out of Bee Creek line, but creates a new lift station and requires replacement of adjacent trunk line

3. Pump west side flow into adjacent sub-basin to the south

$20 million Moves flow out of Bee Creek line, but creates a new lift station and requires replacement of adjacent trunk line

4. Build a new treatment plant on the west side

$29 million Increases operational costs substantially

5. Divert west side flow to the Lick Creek treatment plant

Way more Need 11 miles of pipe and very large lift station. Would max out Lick Creek plant, would have to expand it now.

Conclusions

We must proceed with the Bee Creek project• Must avoid sewer line overflows• TCEQ fines/penalties would be significant• Line cleaning project in FY-12 to regain some capacity

RecommendationsApprove awarding Design contract, $1.5 M to Kimley-Horn

Formal approval is on Consent Agenda today

Get design firm to look at alternate solutions firstTarget construction of Phase I to start Oct 2012Review Construction Funding options during Design phase