2013 Georgia Association of. Conference Lake Lanier Islands, Georgia

Transcription

1 Successful Green Infrastructure Solutions for Our Communities David M. Ashley, y, RLA March 14, Georgia Association of Floodplain Managers Annual Technical Conference Lake Lanier Islands, Georgia

2 Green Infrastructure Sustainable watershed and stormwater management solutions that use soil and vegetation to: Consider all sources of pollution in a watershed Maintain and restore the natural hydrologic cycle Advance community health, safety and quality of life objectives Low Impact Development (LID) An integrated site design approach that seeks to mimic the natural or pre-development hydrology of a site (Prince George s County, 1999)

3 reen Infrastructure Challenges Despite benefits, Green Infrastructure (GI) approaches have been elusive in many communities Successful GI solutions require the integration of professional skills, from planning to design to construction to O&M Communities often have some portions of the needed tools to implement GI solutions, but lack others Appropriate skills may be scattered among various departments

4 How do we get There from Here? Communities have taken many different approaches Much of the work done to date has been the result of EPA CSO/SSO Consent Decrees GI/LID techniques in early stages of development, benefits of BMPs may vary widely from place to place Monitoring results from in-place BMPs are only now beginning i to show results

5 USEPA Direction In 2012 EPA issued 6 Fact Sheets and 2 Supplements on GI Implementation: 1) General Accountability Considerations 2) Combined Sewer Overflows (CSO) 3) Sanitary Sewer Overflows (SSO) 4) Stormwater 5) Total Maximum Daily Load (TMDL) 6) Water Quality Standards

6 Important Themes Both Green and Gray practices will likely be required in most urban areas Define standards as desired result and use combinations of Green and Gray to achieve May need Interim as well as Medium- and Long-Term Targets (Quantitative) Monitoring is essential for both construction and O&M Allow for uncertainty y( (Adaptive Management)

7 GI measures may be: Nuggets Integrated into CSO LTCPs Ideal solutions for SSO inflow problems and may reduce capacity requirements Integrated t into MS4 permits (specifying i water volumes to be controlled on-site) Used to reduce the amount of TMDL allocated to future growth Effective tools to help meet Water Quality

8 Common Issues among GI Programs Planning Funding and Economics Community Involvement Hydrology and Hydraulics Studies Ecological Studies Development/Ranking e e of Alternatives es Infrastructure Design Maintenance

9 Planning Most efficient way to incorporate GI solutions is to integrate concepts early in the development process. - Community master planning - Ordinances and standards - Comprehensive park planning - Planning for individual developments (Brook Street Soccer Complex Plans incorporate GI techniques)

10 Planning May not be an easy or expeditious process. Many different local government departments may be involved. Often GI/LID techniques violate existing planning or development policies/regulations. Process may require changes in ordinances/codes that require legislative approval. (J. Todd, City of Atlanta, 2011)

11 Funding and Economics For new development, GI/LID implementation can be required by local governments Many of the larger GI Programs across the country are being implemented because of EPA Consent Decrees ees Major expenditures, from hundreds of millions to billions of dollars. (EPA recently compared 12 cities with GI programs ranging from $3 M to $2.4 B [Struck, Hufnagel and Field, 2012]) ) GI program costs often compare favorably to Gray solutions and may be better received by

12 Funding and Economics Size of the potential investments requires financial planning and potentially rate increases or new revenue sources Virtually every situation is different; custom solutions need to be tailored to accomplish GI goals Choices will not be easy in the current economic climate and will demand prioritization of efforts

13 Community Involvement Taxpayers/ratepayers will ultimately bear the burden of most GI initiatives Both Green and Gray Infrastructure t improvements can affect their daily lives Essential to involve stakeholders and the public and get buy-in to accomplish GI objectives

14 Hydrology and Hydraulics Studies/Modeling Common theme in EPA Fact sheets Existing stormwater/cso systems need to be evaluated to determine: Where problems are Relative cost-effectiveness of various measures How much improvement can be made with GI solutions Mix of Green vs. Gray alternative solutions Quantify compliance targets and GI contribution

15 Ecological Studies Regulatory agencies are increasingly emphasizing stream health and function in addition to numerical water quality goals The flow and volume attenuation provided by LID BMPs can improve stream conditions Generally stream restoration efforts will be more successful in smaller, less urbanized watersheds

16 Amenities Green Infrastructure projects can often be valued community amenities Can garner community support for water quality programs Provide aesthetic and recreational benefits as well as reducing non-point effects Have been powerful catalysts for redevelopment

17 Alternatives Development and Ranking Many systems have been developed to: Analyze potential solutions Develop benefits and costs Rank in order of preference for implementation Range from straightforward (spreadsheet) ranking to modeled d systems that t attempt t to account for a great variety of indirect benefits and costs Should include both financial and non-financial components Triple Bottom Line approaches are common

18 Infrastructure Design Common categories of GI/LID BMPs Bioretention Swales Permeable Pavement Green Roofs Downspout disconnection

19 Infrastructure Design Recent monitoring results indicate that the performance of various measures varies widely from location to location and certainly by region. Benefits: Reduce storm peaks and volume Nutrient/solids t/ removal Groundwater benefits Pitfalls: Limited effects in heavily developed areas Limited pathogen removal Require regular maintenance

20 nual Runoff Volume Reduction Regional Differences can be Significant LID Atlanta Los Angeles Philadelphia Seattle pervious Area Disconnect 5% 6% 23% 7% Rain Garden 68% 45% 88% 59% Grass Bioswale 10% 13% 70% 28% Bioretention 44% 34% 90% 45% Permeable Pavement 88% 83% 99.8% 98% Green Roof 44% 38% 40% 22% m Beyerlein, Regional Differences in the Effectiveness of LID Facilities, Stormwater,, April 2012

21 Successful Green Infrastructure Implementation ey components: Common understanding of the benefits of GI and commitment to quantifiable goals Support of GI/LID at the executive level. Changes to codes and ordinances to enable GI implementation. Public outreach on GI/LID programs to build community support. Coordination among various local government departments Realization of the limits of GI/LID feasibility on developed properties Commitment to GI/LID in operations and maintenance, as well as construction ti

22 GI Design and Maintenance Planning Ecological Studies Financial Issues Hydrology& Public