1. Proposed Storm Water and Grading Policies and Standards
January 13, 2011
Good _______ Mayor and members of Council..
Today I would like to update you on discussions staff has been having with the development community concerning grading and drainage issues.
GS:Today it’s my pleasure to present to you an update on the Storm Water Management Program Project Status
Don McChesney

2. Workshop Agenda
8:30 Welcome and Overview of proposed changes: Don McChesney
9:00 TCEQ construction runoff regulations: Rebecca Scott, SECA
10:00 Break
10:15 Construction runoff enforcement and support: Derek Senter
10:30 Construction best practices: J. W. Lemons, SECA
11:20 Lake Worth Case Studies: Paul Bounds; Scott Berman, FNI
11:40 Wrap-up: Don McChesney

3. Workshop Goals
Inform public of current and proposed regulations affecting storm water design and construction runoff
Receive feedback on proposed changes and how they can be effectively implemented

4. iSWM—what is it? integrated Storm Water Management is:
Managing all aspects of stormwater
collection
conveyance
storage
treatment
to achieve City goals for
protecting people and property from flooding
reducing erosion
protecting water quality of streams

5. iSWM—what is it? by integrating
Development with natural hydrology stormwater with other community needs, where mutually beneficial
public and private stormwater systems
all phases of development from planning through design, construction and maintenance
plan review and inspection processes
“private” water is a public concern—how runoff is handled on private property directly affects flooding and other potential adverse impacts of land development
And more and more, storm water controls are being incorporated into new development to address these concerns…

6. Current Stormwater Issues
Not all development subject to review
Infill development
Single family construction
Private property grading
Construction runoff practices inconsistent with TCEQ standards
City Design Manual needs updating
Construction runoff—not addressed in 2006 Manual

7. Construction Runoff Concerns
Lack of locally adopted, current standards
Inadequate review of erosion control plans
Change of custody by developer/builder
Monitoring of controls
Removal of controls after stabilization
Staff resources

8. Weaknesses in current Design Manual
Construction and post-construction treated independently
Local flooding failures since 2006
Not “user-friendly”
No longer supported by regional iSWM

9. Strategy for addressing needs
Adopt “Grading Permit” tying stormwater to land disturbance and building permits.
Update standards and review requirements as part of adapting iSWM 2010
Involve development community
Emphasize erosion control plans and SWPPP in project review and inspections
Educate staff and public

10. How can we gain compliance with new standards?
Standards must be accepted as “reasonable”
Focus on a few key, simple to understand standards
Challenge non-compliance
Hold individuals to account

11. Proposed Grading Permit
Required for land disturbances of 0.1 acres or more
Cursory review for commercial projects disturbing under 0.5 acres
Engineered drainage plan for disturbances of 0.5 acres or more
Final Grading Certificate required for commercial projects prior to C.O.
Single family building permits tied to subdivision grading plan and standard HUD drainage patterns

12. Grading Permit Requirements for Land Disturbance Activities
How much
land is
disturbed?
No Grading Permit
required
0.5 acres or more
less than 0.1 acres
0.1 – 0.5 acres
iSWM required
Drainage and
Floodplain
Review
Is 1 acre
or more
disturbed? No
Yes
Storm Water
Pollution Prevention
Plan (SWPPP)
required
Check Urban Forestry,
Land Filling and other
City requirements
Final Grading
Certificate
Construction and
grading activities
Grading Permit
Grading Permit Requirements for Land Disturbance Activities

13. Grading Permit
Commercial building permits must have approved iSWM Plan
For site or part of larger area
Adopted since May 2006
Review by Stormwater staff

14. Simplified Drainage Review for Small Building Permits
iSWM by PE not required
Contractor submits site plan showing topography, runoff arrows and nearby stormwater infrastructure
Stormwater staff check for floodplain or other “known” problems

15. Grading Certificate
At end of construction, Engineer or Contractor certifies construction completed per Grading Permit
iSWM
Urban Forestry
SWPPP
Required prior to commercial building C.O.’s

16. Early (Rough) Grading Permit
Requires approval of iSWM Conceptual Plan and Urban Forestry Phase 1 submittal
Allowed prior to completion of detailed construction plans
Rough grading plan can be schematic
Contractor proceeds “at risk”
Final Grading Permit still required.

17. Residential Drainage
Contractor completes application for building permit
- conformance to Subdivision Grading Plan
-Standard HUD lot drainage pattern
Exceptions review by Stormwater staff
Runoff from 3 lots or more must be contained within drainage easement

18. Erosion Control Plan Required as part of Final iSWM Plan
Engineer must certify compliance with City and TCEQ regulations

19. Design standard changes
Thermoplastic pipe usage expanded
Revised runoff coefficients for large SFR lots
Sump Inlets require structural overflow
Area inlets limited to 25 acres; must have drainage easements for collection area
Headwalls required for 25acres drainage area
Low flow pilot channel & culvert encouraged
Thermoplastic pipe usage expanded—driveway culverts, residential concrete pavements; tied to new installations standard
Revised coefficients of runoff for large SFR lots
Sump Inlets—must convey underground Q25+ and have structural overflow for remainder of Q100.
Drop/Area inlets—limited to less than 25 acres; easily accessible; drainage easements for area used to collect runoff
Headwalls—required for 25a+
Low flow pilot channel & culvert-include graphic

20. CFW iSWM Criteria Manual for Site Development and Construction

21. Major changes in 2010 iSWM Format
Policies (“criteria) separated from Technical Standards
Construction and post-construction control integrated
Technical
Major update of Construction Runoff Standards

22. Contents of CFW iSWM Manual
CFW definitions 1.0 Overview of iSWM Criteria Manual 2.0 integrated Development Process 3.0 integrated Design Criteria 4.0 integrated Construction Criteria 5.0 Local Requirements Appendix A – CFW Detailed Checklists and Forms Appendix B – CFW Computer Models Appendix C – CFW Miscellaneous Details and Specs Appendix E – Single Family Residential Lot Drainage

23. iSWM 2010 Technical Standards
Planning
Water Quality
Hydrology
Hydraulics
Site Development Controls
Construction Controls
Landscaping

24. Definitions
Grading Permit – The approval by the CFW to proceed with the disturbance of 0.1 acres or more….
iSWM Construction Plan – An erosion and sediment control plan prepared with the design of permanent improvements in accordance with … this Manual.
iSWM Plan or iSWM Site Plan – A stormwater management plan that conforms to… this Manual.
Stormwater Fee Credits – An incentive …to encourage the voluntary use of BMPs
SWPPP –… plan required by … TCEQ…. The iSWM Construction Plan covers much of the [SWPPP] site design requirements…

25. iSWM 2010 Format Common regional criteria incorporated as general text
“Local Provisions” boxes used for exceptions, clarifications or additions by local agency

26. Example of 2010 Format
iSWMText
COFW Local Provisions
In Box.

27. Step 4 – Prepare Final iSWM Plans and iSWM Construction Plan
An iSWM Construction Plan must be … submitted as an integral part of the final engineering documents.
…SWPPP must be prepared by… qualified professional…. The iSWM Construction Plan… should normally be incorporated into the SWPPP...
If a stormwater facility is provided which qualifies for a Stormwater Fee Credit, the engineer must submit an application.. along with a supporting documentation.

28. Section 3.6.3 Hydraulic Design Criteria for Structures - Culverts
For multiple barrel culverts the CFW encourages the placement of one of the barrels at the flowline… with the other barrels at a higher elevation… reduce sediment and debris accumulation. Where practical the low-flow portion of the low barrel(s) should convey 2% of the design 100-year discharge.

29. 3.7 Easements, Plats, and Maintenance Agreements
…limited perpetual maintenance may be provided by the CFW for riparian areas preserved in their natural state, subject to the approval of the CFW.

30. 4.3 Criteria for BMP’s During Construction
CFW allows flexibility in use of BMP's not listed in the Construction Controls Technical Manual with approval of D-TPW.

31. 4.3.1 Erosion Controls Temporary Stabilization
Portions of a site that have been disturbed but where no work will occur for more than 21 days shall be temporarily stabilized as soon as possible, and no later than 14 days, except when precluded by seasonal arid conditions or prolonged drought.

32. 4.3.1 Erosion Controls Notice of Termination (NOT)
All parties that submitted a NOI shall submit a NOT within 30 days after final stabilization is established. When the owner of a residential subdivision transfers ownership … the SWPPP shall include controls for each individual lot…. Additionally, the builder must submit a valid NOI….

33. 4.3.2 Sediment Controls
Special approval is required by CFW regarding location and design of any inlet controls. Where permitted, the operator will be expected to diligently monitor storm conditions and to remove them when there is a risk of flooding.

34. Implementation Schedule
Detailed discussions with area engineers and DAC
Council ITC briefed November 9
Workshops 12/8-17 & 1/13/11
Adoption by Council: January
Effective date for changes: March
This discussion has been going on for about 12 months, so you may have picked up on some of these conversations.
We have had 5 public meetings with area engineers since January, where we’ve reviewed drafts of policies and standards in detail.

35. Resources
Draft CFW iSWM Manual and adopted Stormwater Credit Manual are posted on Buzzsaw: Resources/20 - PM and Consultant Tools/Storm Water folder
iSWM Technical Standards are posted at:

36. Grading Permit New review emphasis New review starting point
Type
Size
New review starting point
Using existing design standards
Additional review
New review end point

37. Grading Permit Requirements for Land Disturbance Activities
How much
land is
disturbed?
No Grading Permit
required
0.5 acres or more
less than 0.1 acres
0.1 – 0.5 acres
iSWM required
Drainage and
Floodplain
Review
Is 1 acre
or more
disturbed? No
Yes
Storm Water
Pollution Prevention
Plan (SWPPP)
required
Check Urban Forestry,
Land Filling and other
City requirements
Final Grading
Certificate
Construction and
grading activities
Grading Permit
Grading Permit Requirements for Land Disturbance Activities

38. Final Grading Permit

39. Final Grading Permit, Continued

40. Early Grading Permit

41. Final Grading Certificate

42. Final Grading Certificate, Continued

43. FHA/HUD Grading

44. 5.11 Grading Requirements Next to Building Foundation

45. 5.5 Storm Water Facility Maintenance Agreements
Exhibit A – Legal Description
Exhibit B – Design Plan and Specifications
Design Data and Calculations
Schematic Plan
Landscaping
Exhibit C – Operations and Maintenance Plan
Exhibit D – Maintenance Checklist

46. Figure 5.9 Example Schematic for Dry Detention Basins

47. Engineer’s Checklist for iSWM Plan, Continued
iSWM Construction Plan
Existing and post-development topography and drainage features
Limits of disturbance
BMP design
Location, details, calculations for sediment controls
Location, details, calculations for waste controls
Sequence of construction phases
Phasing of temporary and permanent stabilization
Temporary control structures that will be converted to permanent structures
Sediment Traps
Top soils banked on-site

48. Questions?