1. LOW-IMPACT DEVELOPMENT
Opportunities for Flood Mitigation
Name, title,
I want to draw some clearer links between LID and its impact on flood mitigation

2. Houston Area Population Density
Region is growing … adding 3.5 million by 2040
No surprise, just look at the map
2015
2040

3. Development Impacts by 2040
6 million more parking spaces
680 million sq. ft. more non-residential development
3.5 billion sq. ft. more residential development
Along with population growth comes need for infrastructure, housing, retail, and other businesses
6, 680, 3.5

4. Development Impacts by 2040
390 Cinco Ranches
230 NRG Parking Lots
To put it in perspective with a fun statistic – that is the equivalent 390 additional Cinco Ranches…
1,400,000 single family housing units 2040
3,594 housing units in Cinco Ranch (2010)
1,400,000/3,594 = 390 Cinco Ranches
4,725,464 ft or 894 miles linear feet of roadways
… and 230 NRG parking lots.
Which is one of the world’s largest parking lots (26,000 spaces)
NRG Park holds 26,000 parking spaces (26,000* 270 = 7,020,000 sf of parking; 7,020,000) 6million spaces* 270sf of parking spaces/ 7,020,000 =230NRG Park parking lots
Fuellingkaty.com
hinrgareahotel.com

5. Designing for Impact Guide Workshops Mapping Tool
We wanted to think about the role of low impact development (LID) in this growth, so we created a guide called Designing for Impact to provide information and strategies for educating the public about LID functions, benefits, and solutions to overcome barriers to implementation.
Guide:
Made with input from regional stakeholders
LID functions
Benefits
BMPs
and solutions for overcoming obstacles to implementation
Includes case studies
Workshops
3 workshops for participants from public and private sectors, advocacy groups and interested citizens
Mapping Tool
Includes over 60 LID projects, and anyone can add to it.

6. Designing for Impact h-gac.com/go/LID Ghirardi Family WaterSmart Park
The LID webpage can be found at
Or you can google H-GAC LID
It includes
Information on the Designing for Impact project and Upcoming Events
Resource Documents on LID
LID Photos
Interactive mapping tool that highlights the locations of LID projects around the region
The Regional Guide to LID

7. What do we know? LID mimics nature Slows Diverts Captures
Mimics the natural conveyance of stormwater by redirecting it in a number of different ways that can both capture, slow and/or redirect stormwater. This reduces the chances for flooding, both on-site and downstream by reducing both the volume of water and the rate of waterflow.
Design Workshop
Asakura Robinson

8. What do we know? Swiss Army Knife, not a silver bullet
Knife image created by Robert Bjurshagen from the Noun Project

9. What’s do we know? Swiss Army Knife, not a silver bullet
Knife image created by Robert Bjurshagen from the Noun Project

10. LID is a Swiss Army Knife
Asakura Robinson
Asakura Robinson
Asakura Robinson
Design Workshop
Our guide describes 12 distinct strategies. As a development strategy, it’s adaptable to site-specific needs
Multi-purpose
Jones + Carter
Asakura Robinson
Harris County Public Infrastructure
Knife image created by Robert Bjurshagen from the Noun Project

11. LID is a Swiss Army Knife
Reduces runoff
Filters stormwater
Adds aesthetics
Increases value
Multi-benefit
Cuts costs
Knife image created by Robert Bjurshagen from the Noun Project

12. Won’t fix everything, but is still highly useful
Flood Mitigation and LID
Won’t fix everything, but is still highly useful
It isn’t the final answer, but it can be part of the solution.
It is adaptable to the specific needs of any project.
When it comes to understanding the impact of LID on stormwater runoff, there is no single definitive study, but some research has been done on some LID tools. Many variables to understand: the effectiveness of one specific LID tool will depend on the amount and speed of rainfall and the state of the soils, for example.
Knife image created by Robert Bjurshagen from the Noun Project

13. Permeable Pavement
A 1,000 sq. ft. driveway can produce more than 600 gallons of stormwater runoff in a 1-inch rainfall.
Source: URS Group Inc., 2010

14. Permeable Pavement Permeable pavement can absorb 80-100% of rainfall
Considerations:
Slope of pavement
Soil content below pavement
Size and distribution of storm events
Infiltration rate
Frequency of surface cleaning
Source: Center for Neighborhood Technology, 2010

15. Natural & Constructed Wetlands
A one-acre wetland can typically store about three-acre feet of water, or one million gallons.
Source: U.S. Environmental Protection Agency, 2006

16. Natural & Constructed Wetlands
Wetlands reduce flood damage by $8,000 per acre each year.
Source: The Conservation Fund

17. Natural & Constructed Wetlands
Preserving 15% of the land area of a watershed in wetlands can reduce flooding peaks up to 60%.
Source: U.S. Environmental Protection Agency, 2006

18. Natural & Constructed Wetlands
Site Design is key
Images: Design Workshop

19. Green Roofs
Multiple studies show that green roofs can retain 40-80% of annual rainfall.
Source: Center for Neighborhood Technology, 2010; Image: H-GAC

20. Policy Solutions Wide minimum roadway widths Narrower roadway design
Curb & gutter requirements
Make requirements flexible
Excessive impervious cover
Efficient site design
Lack of incentives
Incentives to lower costs and risks
Source: Center for Neighborhood Technology, 2010; Image: H-GAC

21. Local Examples
Site design:
220 acres and 660 housing units

22. Thank You
Site design:
220 acres and 660 housing units