PineyPoint

Document Sample
PineyPoint Powered By Docstoc
					               Piney Point
            Sewer System
Studies show that this system is a major source of
Inflow entering the Marlay-Taylor collection system
   All sewer lines have been televised and smoke
tested to evaluate the condition of system and many
                 problems were found
    The system has a long history of near miss
overflows during rain events and its proximity to the
        Potomac River is cause for concern
Inflow – is when water enters a sewer system
during and immediately after a rain event. It
enters the system through broken pipes,
misaligned joints and sometimes through
improperly connected down spouts or sump
pumps.
Infiltration – is when groundwater enters the
system when groundwater levels are high
and covering the buried pipes. It enters the
system through broken pipes or misaligned
joints.
During wet months of the year when groundwater
 tables are high, the average flow at this pump
        station is 195,000-233,000 GPD
During dry months of the year when groundwater
 tables are low, the average flow at this pump
        station is 170,000-175,000 GPD
 During a significant rain event, the flow passing
through this pump station has been measured as
         high as 269,000-418,000 GPD
All significant rain events require the use of Septic
       Haulers to prevent sewage overflows
Piney Point Collection System Flows, Excess of Average
       Flows Resulting from Heavy Precipitation
                      Flows in Excess of Average, Precipitation Event




                                                         PPL
                                                         14%




                                                                             SGI
                                                                             17%


             PP Gravity
               55%




                                                                   Sheehan
                                                                     14%




                                PPL   SGI   Sheehan   PP Gravity
                             Piney Point Flows August 2004 Rain Event

            1                                                                      4.5
                                                            0.934

           0.9                           4.1
                                                                                   4

           0.8
                                                                                   3.5
           0.7
                                                                                   3
           0.6




                                                                                         Rain inches
Flow MGD




                                                                                   2.5
           0.5
                                                                                   2
           0.4
                                                                         0.308     1.5
           0.3

                  0.178              0.178                                         1
           0.2
                                                                0.6
           0.1                                                                     0.5
                      0.18
            0                                                                0     0
                 1-Aug-04           2-Aug-04              3-Aug-04      4-Aug-04
                                                Date

                                         Flow MGD      Rain inches
     Several methods for repairing the sewer system were evaluated to
 determine the most economical and effective way to resolve the problems
identified as shown below. Please note that these are rough estimates and
        will change when a more complete design is commissioned.


                                        Pipe Bursting/
                                          Directional       Pipe Bursting/
                                            Boring-       Directional Boring-
  Cured In Place     Fold and Form         Installing     Installing C900/RJ
     Lining              Lining         C900/RJ Pipe              Pipe
     $210,016           $291,564          $265,743             $366,161




                                            Open
  Pipe Bursting/     Pipe Bursting/      Excavation-
Directional Boring-   Directional       Installation of
 Installing HDPE    Boring-Installing     8" SDR-35
        Pipe           HDPE Pipe             Pipe          Grinder Pumps
     $325,348           $257,054          $420,632             $604,581
        Piney Point Sewer System
    Project Cost Estimate = $878,900
        Loan Interest Rate = 1.6%
         Loan Period = 20 years
    Annual Debt Service = $47,264/yr.
Funds to Repay this Debt will be recovered
  through the Commission’s Operation &
           Maintenance Budget

				
DOCUMENT INFO