1. WORKSHOP I: Green Infrastructure Overview Construction, Inspection, and Maintenance
Stormwater BMP Maintenance DPW Staff and Municipal Stormwater Managers

2. WHY DOES THIS MATTER? STATE AND LOCAL AGENCIES OWNERS & OPERATORS
OPERATION AND MAINTENANCE
REGULATIONS AND DESIGN MANUALS
STATE AND LOCAL AGENCIES
OWNERS & OPERATORS
DESIGNERS
CONSTRUCTION DRAWINGS
INSTALLATION
CONTRACTORS

4. HOW CAN WE AVOID THIS?
1 Drainage Inlets 2 Swales & Conveyance 3 Sediment Forebays 4 Treatment Areas (Bioretention/ Gravel Wetland) 5 Overflow & Spillways 6 Surrounding Area Vegetation Long-Term Maintenance
Why proper installation/materials are important
Importance of maintenance

5. 1 DRAINAGE INLETS Diversion structures Pipe Inlets Trench grates
Curb Cuts
Paved inlet flumes
Catch basins
Why proper installation/materials are important
Importance of maintenance

6. CONSTRUCTION
Ensure it is located at the low point and water can enter easily.
Set stones flush to allow water to flow in.
Watch for sediment accumulation

8. MAINTENANCE Clean sediment/lead litter from inlets Watch for scouring
Inlet Clogging

9. LESSONS LEARNED Stones prone to clogging
Curbing increases side slope and depth
When applicable zero curb
Allow for sheet flow
Diversion structure can problematic for retrofits
Retrofit existing structures
Benefits
Improved Aesthetics
Shallow depth
Easier maintenance
Reduce cost

10. 2 SWALES & CONVEYANCE Grass swales Vegetated swales
Turf reinforced (TRM) swales
Stone swales
Why proper installation/materials are important
Importance of maintenance

11. CONSTRUCTION Ensure positive drainage Check dams to prevent erosion
No by-pass

12. MAINTENACE Debris Cleanout Sediment/Organic Debris Removal
Check for areas of erosion/ gullies in the swale, particularly along the swale bottom.
Repair/reseed as necessary
Overtopped berm

13. Sidewalk was removed
RI Gro native grew many of the native plants and 50 volunteers assisted with planting each of the sites.

14. 3 SEDIMENT FOREBAYS Why proper installation/materials are important
Importance of maintenance

15. CHECK DAMS

16. SEDIMENT FOREBAYS Bioswales: Leaf clutter causing death of plants
Source:
Source: Aaron Volkening bioretention Pabst Brewery
Bioswales: Leaf clutter causing death of plants
Pervious Pavers: off -site runoff clogging system
Forebay: Discuss design options, mosquitoes problems
Inlets: too small, Silt damming

17. SEDIMENT FOREBAYS

18. MAINTENANCE Remove trash and debris from the surface.
Signs of erosion gullies, animal burrowing, overtopping or slumping are observed. Repair as necessary.
Remove sediment accumulation and properly dispose when accumulation is greater than or equal to 3 inches or you cannot see stones.*

19. LESSONS LEARNED Early Designs Inlets/forebays with rip/rap or stone
Forebays large/difficult to clean
Lessons Learned
Smaller forebay/more frequent cleaning
Use a hardscape smooth surface at the bottom
Aha moment - Spend time during construction trying to keep sediment out at the inlet. Why nor design this way with more frequent cleaning
Stone at inlet set too high- traps sediment at the paved flume. Incorrect installation, but why not design to trap sediment before entering the treatment area.

20. 4 TREATMENT AREAS Why proper installation/materials are important
Importance of maintenance

21. CONSTRUCTION ELEMENTS

22. GRAVEL UNDERDRAIN JACKET
AASHTO M-43 standard
Washed, clean and free of all fines

23. UNDERDRAIN PIPE CLEANOUT
4” rigid schedule 40 PVC pipe with 3/8” 6” O.C. meeting ASTM D 1785
T’s and Y’s as needed depending upon the underdrain configuration

24. PEA GRAVEL 3/8” Washed stone
Between the soil media layer and approved sub grade, underdrain gravel chambers, etc.

25. SOIL MIXES USDA soil type loamy sand or sandy loam
Filter Media to contain:
85-88% sand
8-12% Soil Fines
< 2% clay
3-5% Organic Matter
Organic Matter
Well aged (6-12 months), well aerated, leaf compost or approved equivalent

26. MAINTENANCE Debris Cleanout
Signs of erosion gullies, animal burrowing, overtopping or slumping
Sediment/Organic Debris Removal
Vegetation Maintenance & Replacement
Water Draining properly
If standing water is observed for more than 48 hours after a storm event maintenance required

27. LESSONS LEARNED Early Designs 6”-12” depth Flat bottom – zero slope
Became too deep
Side slope stabilization
Curb and gutter systems
Lessons Learned
Shallower depth has advantages
Use check dams
More cells
Benefit
Aesthetics
Improved Function
Easier Maintenance
Source: Los Angeles Zoo designed by others

29. 5 OVERFLOW & SPILLWAYS Overflow/Outlet Structures Spillways
Why proper installation/materials are important
Importance of maintenance

30. CONSTRUCUTION Fiberglass Nyloplast (ADS, Inc.) catch basin structures
With frame and grate
Typically 24” Diameter with main outlet and 1 to 2 underdrain inlets

31. CONSTRUCUTION

32. MAINTENANCE EMERGENCY SPILLWAYS
Check for settling gulling, erosion damage, settling & clogging
Repair as necessary and return to design grades
OVERFLOW STRUCTURE
Check for sediment accumulation that impacts inflow. If sediment accumulation. Schedule cleaning
Check for leaf litter, debris and inlet clogging

33. 6 SURROUNDING AREA Debris Removal Pavement Sweeping Drainage Network
Remove trash from perimeter areas.
Pavement Sweeping
Sweep parking lot minimum once a year after spring thaw.
Drainage Network
Ensure proper operation.
Contributing drainage area stabilized
Why proper installation/materials are important
Importance of maintenance

34. VEGETATION 10:00 – 10:30 GI Maintenance Activities (4 slides)
Vegetation management and maintenance – importance of plant lists and understanding native plants vs. invasives

36. WEEDING Why Weed? Control invasive plants
Promote native non-invasive plant growth
When to weed?
April thru October
Monthly
Do not use chemical herbicides
Remove by hand
A list of invasive species can be found at:
cipwg/invplantsCT05.pdf

37. WEEDS

38. WEEDS

39. WEEDS

40. WEEDS

41. PRUNING AND THINNING Why Prune? Maintain plant health and vigor
Removal of dead or broken wood
Encouragement of flowering and fruiting
Control of overgrowth of plant material
Image courtesy of Rutgers New Jersey Agricultural Experiment Station

42. TOO MOW OR NOT TO MOW ?

43. THAT IS THE QUESTION ?

44. WORK WITH NATURE Visible/Easily understood Sedges/rushes/cattails
Fescues/Joe pye weed
Wildflower
Mimic Nature
35% Creeping Red Fescue (Festuca rubra)
35% Chewings Fescue (Festuca rubra ssp. commutata)
10% Hard Fescue, 'Heron' (Festuca ovina var. duriuscula (F. longifolia), 'Heron')
10% Hard Fescue, 'Chariot' (Festuca brevipila, 'Chariot')
5% Kentucky Bluegrass, 'Blackjack' (Poa pratensis, 'Blackjack')
5% Kentucky Bluegrass, 'Clearwater' (Poa pratensis, 'Clearwater')

45. GRASS SEED/SOD
Low Mow Fescue, New England Conservation/Wildlife mix or approved equivalent
To be used on side slopes and bottoms
Sod can be used for faster results, but will increase the cost

46. FERTILIZING Fertilization should not be necessary
Compromises pollutant reduction effectiveness
Leads to weak plant growth
Promotes disease and pests
Inhibits soil life

47. SHORT-TERM MAINTENANCE
Why Inspect?
Ensure proper design function after construction
When to inspect?
6 months period after construction
Monthly during an immediately after construction
After rain events of 1” and greater
What to inspect?
Erosion and Gullying
Grass/Plant growth
Washouts Inlet flumes or pipes inlets
Sediment forebay
10:00 – 10:30 GI Maintenance Activities (10-12 slides)
Typical routine and long-term maintenance measures

48. Long Term Operation and Maintenance48

49. INSPECTIONS When to inspect? What to Inspect? Spring thru fall
During the typical routine landscape maintenance:
Once per month
After large storm events
During other extreme weather events
What to Inspect?
Debris Accumulation
Sediment build up
Weeds and invasive plants
Plant and grass health
Erosion/Gullying
Inlet/Outlet structure clogging

50. THANK YOU!
QUESTIONS?

51. WORKING WITH NATURE Chepachet WVTS
Integrated into the site/future park
Removal of invasives
Brownfield site
October Glory Swamp Maple Shadblow Juneberry Whitespire Senior Gray Birch Swamp White Oak
Red Chokeberry White Summer Sweet Silky Dogwood Red Osler Dogwood Southern Gentleman Winterberry Winter Red Winterberry Spice Bush Highbush Blueberry Arrowwood Viburnum
Joe-Pye Weed Blue Flag Royal Fern Virginina Creeper Pickerelweed Arrow-head, Wapato Duck Potato Wool Grass Three-Square Bullrush American Burreed

52. SEDIMENT & DEBRIS When? Debris Sediment
Upon completion of construction
After Construction
Debris
Once per month or as required
Sediment
Minimum of once per year
After major storm events
After 1” of sediment accumulation.
Typically early Spring

53. SEDIMENT & DEBRIS Excessive sediment accumulation
Check surrounding site stabilization
Hand remove with a flat shovel
If surface becomes clogged
Core aerate or cultivate bare areas annually

54. PRESENTATION OUTLINE
8:45 – 9:30 GI Construction Issues and Maintenance Activities (40 slides)
Why proper installation/materials are important (10 slides)
Common construction problems and proper construction inspection (4 slides)
Importance of maintenance (1-2 slides)
Vegetation management and maintenance - importance of plant lists and understanding native plants vs. invasives/weeds (6-7 slides)
Typical routine and long-term maintenance measures, including frequency and duration (7 sides)
Discussion of Cape Cod-specific construction and maintenance issues and Lessons learned (10 slides)