latest findings by consultant team about panther hollow, may 23, 2011

PANTHER HOLLOW:INTERVENTIONS FOR WATERSHED RESTORATION

MAY 23, 2011

PROJECT GOALS

• Understand Panther Hollow hydrodynamics.

– Natural and Existing

• Develop attainable surface water goals.

– Return baseflow to Phipps Run and Panther Hollow Stream.

– Mitigate the “flashiness” of runoff during heavy storm

events.

• Identify range of possible interventions & priority

locations for pilot projects.

• Identify opportunities in the 4 Mile Run Watershed

• Create a watershed restoration plan for Panther

Hollow

• Design and construct three pilot projects in the

watershed.

REVISED PANTHER HOLLOW WATERSHED BOUNDARY

ORIGINAL AREA = 780 AC REVISED AREA = 384 AC

PRE-COLUMBIAN SUBBASINS

PHIPPS RUN = 67 AC PANTHER HOLLOW STREAM = 300 AC

PANTHER HOLLOW LAKE = 13 AC

DIRECT DRAINAGE TO PANTHER HOLLOW

PHIPPS RUN = 67 AC PANTHER HOLLOW STREAM = 97 AC

PANTHER HOLLOW LAKE = 13 AC

LAND COVER

Visitor’s Center

Phipps

First Tee

Golf Course

• Fair to Good: average urban forest

condition

• Poor to Fair (hydric areas): less than

50% canopy coverage with invasive

species within a probable wetland area

• Poor to Fair: less than 50% canopy

coverage with invasive species

Poor-Fair

Woodland and Turf

LAND COVER

Fair-Good

Woodland

and Forest

Poor-Fair

Hydric

Woodlands and Emergent

Marsh

LAND COVER

WHAT’S HAPPENING NOW?

Water from these areas typically makes its way into the CSO.

Clogged inlets

Steep slopes and low curbs could allow for runoff to reach the watershed during heavy storms.

Crowned street

WHERE IS THE RUNOFF COMING FROM?

Land Cover Runoff Volume by Land Cover

POTENTIAL STRUCTURAL INTERVENTIONS

• Reduce Impervious Cover – Street Edge Measures

• Rain Gardens/ Bioretention and Vegetated Swales

• Pervious Pavement

• Infiltration Basins, Beds, Dry Wells, Trenches,

Continuous Tree Trenches

• Forest Restoration

POTENTIAL NON-STRUCTURAL INTERVENTIONS

• Protect/Utilize Natural Flow Pathways to Slow Down

Stormwater and Reduce its Volume

• Landscape Restoration

• Landcover Conversion

• Stop Mowing or Less Mowing

• Sustainable Landscape Management Practices

• Golf Course Management

• Right-of-Way Management

• Meadow and Forest Management

PHIPPS RUN BASIN

• Watershed with historic stream.

• Road was constructed over the stream.

PHIPPS RUN BASIN

PHIPPS RUN BASIN

• Where is runoff coming from?

• What are the constraints?

- Road bisects

- Golf course

PHIPPS RUN BASIN | INFILTRATION TRENCH

• Walk through potential interventions

- Swale behind trees

- Pedestrian walking down street

MAP OF PHIPPS (MED – AA to revise)

Reduce Impervious – Street Edge Measures

PHIPPS RUN BASIN | POROUS PAVEMENT

• Walk through potential interventions

- Swale behind trees

- Pedestrian walking down street

MAP OF PHIPPS (MED – AA to revise)

Pervious Pavements

PHIPPS RUN BASIN |

RAIN GARDENS AND VEGETATED SWALES

Reduce Impervious – Street Edge Measures

Reduce Impervious – Street Edge Measures

Rain Gardens and Vegetated Swales

Rain Gardens and Vegetated Swales

PHIPPS RUN BASIN | WET MEADOW

WET MEADOW

PHIPPS RUN BASIN |

LANDCOVER CONVERSION

LANDCOVER CONVERSION |

turf to meadow, turf- woodland

LANDCOVER CONVERSION |

turf to meadow, turf- woodland

PHIPPS RUN BASIN |

FOREST ENHANCEMENT

PHIPPS RUN BASIN |

FOREST ENHANCEMENT AND EROSION CONTROL

PANTHER HOLLOW BASIN

• Watershed with historic stream.

Stream was beheaded by neighborhood

development.

PANTHER HOLLOW BASIN

• Where is runoff coming from?

• What are the constraints?

- Pros:

- Cons: Steep slopes, eroded soils

PANTHER HOLLOW BASIN

PANTHER HOLLOW BASIN | STORAGE & SLOW

RELEASE

PANTHER HOLLOW BASIN |

STORAGE AND SLOW RELEASE

PANTHER HOLLOW BASIN |

STORAGE AND SLOW RELEASE

PANTHER HOLLOW BASIN |

STORAGE AND SLOW RELEASE

PANTHER HOLLOW BASIN |

LANDCOVER CONVERSION

PANTHER HOLLOW BASIN |

LANDCOVER CONVERSION

PANTHER HOLLOW BASIN |

LANDCOVER CONVERSION