This presentation provides an overview of a potential project to relive neighborhood flooding and sanitary sewer issues in an area of Philadelphia that is served by a private sewer. This was delivered in a face to face meeting with residents in the vicinity of Spring Lane and Hendren Street on November 12, 2013.

1. Spring Lane and Hendren Street
Proposed Flood Relief Project
November 12, 2013
www.phillywatersheds.org

2. Outline
Review of Past Problems and Project
Objectives
PWD Involvement and Initiatives
Watershed and Neighborhood Findings
PWD Proposed Contributions to Solutions
Homeowner Involvement
Choices and Decision Making

3. Hendren Street and Spring Lane
Review of original problem
Stabilize the Spring Lane Outfall
Protect the existing 4” force main
Address the flooding impacts
experienced by residents

6. Infrastructure Damage: Failed Outlet700 Block Spring Lane

7. Infrastructure Damage: Failed Outlet 700 Block Spring Lane

8. Impaired Driver Safety: Standing Water700 Block Spring Lane
PONDED WATER
LIMITS AFTER JUNE
2013 THUNDERSTORM

9. Impaired Driver Safety: Sediment Deposition
@ Hendren & Spring Intersection

10. Roadway/Lawn Interface Deterioration
Eroded gutter@ Hendren & Spring Intersection

11. Homeowner Impacts: Erosion and Pavement
Damage- 600 Block Hendren Street

12. PWD Involvement and Initiatives
Initiative 1:
Homeowner Surveys
Quantify number of homeowners adversely affected by
stormwater runoff
Concurrently gather data to evaluate provision of sanitary
sewer service
Initiative 2:
Analysis
Determine Source(s) and destinations of problematic runoff
Evaluate Potential remedies
Initiative 3:
Recommendations

13. PWD Survey Response Summary
45 Surveys Distributed / 19 Responses (42%)
15 Surveys on Spring Lane/ 7 Responses (47%)
30 Surveys on Hendren / 12 Responses (40%)

15. PWD Survey Summary: Septic
ID
Good Condition
Fair Condition
Poor Condition
Spring Lane
4
2
1
Hendren Street
3
5
4
Total
7
7
5

16. PWD- Analysis- Source of Runoff
Drainage Area to Spring Lane is approximately 25
Acres

18. Runoff Sources: Manatawna Avenue to
Spring Lane

19. Runoff Sources: Hendren Street and
Yards to Spring Lane

20. Summary of Observations:
PWD’s installation of storm sewers/inlets in
Manatawna Avenue, Hendren Street and Spring
Lane will provide control of stormwater from city
streets and public rights-of-way, however, runoff
from private property, driveways and roof tops will
need to be directed and connected to this
infrastructure.

21. Manatawna Stormwater Improvements
Inlets can be added in Manatawna to intercept this
street runoff
HOWEVER, this represents only a small fraction of
the total land area currently contributing to
Hendren and Spring flooding.

22. PWD Analysis: Runoff Path
Yards
Hendren Street
Colonial Swale and Yards
Residences
Low Point in Spring (Damaged Storm pipe and
Headwall)

23. Runoff Paths: Colonial Gutter

24. Runoff Paths: Yards-Hendren to Spring

25. Runoff Paths: Streets- Spring to Field

27. Runoff Paths: Streets -Low Point Spring

28. PWD Analysis: Significant Runoff
Generators
Surface Character affects the amount of runoff
Impervious Surface like roofs, drives, streets and walks
prohibit infiltration of stormwater. Nearly 100%
Runoff
Pervious, Vegetated Surfaces absorb some runoff,
however runoff still occurs, especially in more intense
storms

29. Watershed Statistics: Impervious
Surface
25 Acres Total Drainage Area
25% Impervious (6.3 acres)
2.3 acres streets (public)
4.0 acres roof tops and driveways (privately owned)
75% Pervious (18.6 acres – privately owned)

30. Public vs. Private Runoff Generators
Runoff from streets and public rights-of-way
2.3 Acres or 9%
Yards, roofs and driveways
18.5 acres + 4 Acres = 22.5 Acres or 91%

31. Sanitary Sewer Service
Existing Sanitary Challenges
Of the respondents to the survey, 62% indicated that their
existing septic system was only in “fair” or “poor”
condition

32. Sanitary Sewer Design Considerations
Spring Lane
South side of Spring served by a standard depth
gravity sewer.
A new pump station will require acquisition of additional
right-of-way

33. Sanitary Sewer Design Considerations
Hendren Street
South side residents (uphill) can be served by standard
depth (8-feet Separate) sewers
North side residents (downhill) are below standard depth
sewers

35. PWD Stormwater Remedies:
Localized Damage solution is available; Repair
damage at Spring Lane outfall
Interim: Armor and reinforce

36. Typical Repair of Damaged Outfall

37. PWD Stormwater Remedies:
Construction of a Storm Sewer pipe and inlet system
in public rights of way is possible
Will provide for safe conveyance of captured runoff
Will fortify repair of damaged Spring Lane outfall and
protect forcemain

38. Actions Required beyond PWD’s
Proposed Stormwater Remedies:
Doesn’t Solve the Entire Problem
Requires that private property runoff be redirected to
intercept 100% of runoff
Will not resolve homeowner flooding emanating from
private property runoff

40. Stormwater: Increase Effective Runoff
Collection – Connect All Roofs to Proposed Main

41. Stormwater: Increase Effective Runoff
Collection – Connect All Roofs to Proposed Main

42. PWD Sanitary Sewer Remedies:
Construction of Sanitary Sewer and Pump station is
possible
Will provide alternative to replacement of failing
septic systems
Requires additional efforts to provide service to entire
neighborhood
Downslope properties that have plumbing discharge below
street level may need to install ejector/grinder pumps

44. Choices Related to PWD Action
Construction Impacts
Financial and Action Commitment

45. Choices Related to PWD Action
Construction Impacts
Potential roadway changes
Widening
ADA Walks
Curbs or swales
Driveway crossings
Tree, Shrubbery and Fence Removal Probable

46. Construction Choices Related to PWD
Action: Fence POTENTIALLY at Risk

47. Construction Choices Related to PWD
Action: Fence POTENTIALLY at Risk

48. Construction Choices Related to PWD
Action: Trees POTENTIALLY at Risk

49. Construction Choices Related to PWD
Action: Shrubbery POTENTIALLY at Risk

50. Construction Choices Related to PWD
Action: Shrubbery and Specimen Tree at Risk

51. Consequences of PWD Action:
Shrubbery and Specimen Tree at Risk

54. ALTERNATIVE APPROACH
Reduced extent of curbing and street widening
Intercept Runoff with Roadside Swales in-lieu of
Curbing
Retain Neighborhood Character
Provides Infiltration
Reduces Runoff Volume
Improves Water Quality

55. Alternative Approach: Hendren Street
Section @ Regulated Width

56. Alternative Approach: Hendren Street
Section - Retained Narrow Width- No Curb

57. Choices Related to PWD Action:
Financial and Action Commitment
PWD Responsibility
Homeowner Responsibility
3540 feet of Storm Water Main: Construct, Own &
Maintain
3293 feet stormwater laterals and appurtenances from
downspouts to edge of street: Construct, Own & Maintain
462 feet stormwater laterals to edge of street: Construct
only. (will be owned and maintained by homeowner)
Decommission septic system
3075 feet of Sanitary Sewer Main: Construct, Own &
Maintain. 453 feet sanitary laterals to edge of street:
Construct only. (will be owned and maintained by
homeowner)
3806 feet sanitary laterals and appurtenances from
house to edge of street including : Construct, Own &
Maintain
Pump station and + 700 Feet of Forcemain: Construct,
Own & Maintain
Grinder Pump (if required): Construct, Own & Maintain
Inlets: Construct, Own & Maintain
Swales: Construct, Own & Maintain
Pay Assessment fee: $9.00/lineal foot of frontage
Driveway restoration in area of disturbance only
Pay monthly service fee
Remove vegetation within construction limits*
Acquire permits and approvals for construction within the
public rights-of-way, Only
*
Acquire permits and approvals for construction within
homeowner property limits
Landscaping outside the right of way that is affected by construction will be replaced with young nursery stock of similar species. Landscape replacement
within the right of way will be replaced depending on the situation. Utility, safety and maintenance issues will be evaluated.

58. Steps to Obtain Public Sewers
Residents signed petition to PWD or their
Councilperson
City Council Ordinance is required for a public
sewer
Process from Ordinance to construction can take a
few years

59. Impact to Customers
Each property owner is assessed at the rate of
$9.00 per linear foot of property frontage
Plumbing which drains to the back of the house
needs to be redirected to the front of the house
(PWD has zero interest loans available)
Yard drains, downspouts should be connected to new
stormsewer via new stormwater lateral (PWD has
zero interest loans available)

60. Benefits of PWD Actions
Reduced runoff from street and connected
roofs…reduced property damage
Improved Driver Safety-Reduced standing water
Elimination of maintenance associated with on-lot
septic system
Alternative to replacement of expensive on-lot
septic system
Improved marketability of property

61. Homeowner Solution Choices
PWD Installation of Stormwater and Sanitary
Sewer conveyance System?
…or
Limit PWD’s actions to Repair of Damaged
Spring Lane outfall?
Other?