On 17 and 18 June 2020 the EPA held its National Water Event as an online conference.
This year's theme was 'Restoring our waters'.
This years event was free to attend. It was the EPA's largest water event ever, with over 1250 attending.
To everyone who joined us: thanks for attending; thanks for your probing questions; thanks for your passion; thanks for caring about our waters. We can achieve more working together.
Special thanks to all our presenters and the team who worked behind the scenes to make sure this years conference happened.
For science and stories about water quality in Ireland, check out www.catchments.ie
On 17 and 18 June 2020 the EPA held its National Water Event as an online conference.
This year's theme was 'Restoring our waters'.
This years event was free to attend. It was the EPA's largest water event ever, with over 1250 attending.
To everyone who joined us: thanks for attending; thanks for your probing questions; thanks for your passion; thanks for caring about our waters. We can achieve more working together.
Special thanks to all our presenters and the team who worked behind the scenes to make sure this years conference happened.
For science and stories about water quality in Ireland, check out www.catchments.ie
Ronald T. Green, Ph.D., P.G., F. Paul Bertetti, P.G.,
and Nathanial Toll Geosciences and Engineering Division Southwest Research Institute® Presented on behalf of the Irrigation Panel - TWCA Annual Convention 2015
The importance of groundwater surface water interaction - a case study on Rio...The Texas Network, LLC
Presented by Ronald T. Green, Ph.D., P.G., F. Paul Bertetti, P.G., and Marques Miller
at the Texas Water Conservation Association Conference in The Woodlands, Texas - March 2014
On 17 and 18 June 2020 the EPA held its National Water Event as an online conference.
This year's theme was 'Restoring our waters'.
This years event was free to attend. It was the EPA's largest water event ever, with over 1250 attending.
To everyone who joined us: thanks for attending; thanks for your probing questions; thanks for your passion; thanks for caring about our waters. We can achieve more working together.
Special thanks to all our presenters and the team who worked behind the scenes to make sure this years conference happened.
For science and stories about water quality in Ireland, check out www.catchments.ie
CAWASA Inc. e-Source Magazine July - September 2015 | Caribbean Water And Sew...CAWASA
Caribbean Water Operators provide absolutely essential services across the region. But they are so down-to-earth and close to the
ground that they often go un-noticed. Remembered mainly in cases of emergency, they fix the nation’s water problems so quickly and
efficiently. They come and go in communities affected by water problems and quickly fix pipes and fittings to restore the flow of this
important source, without any waste of time – or water. The region’s water operators are accustomed to going hardly noticed. But they
were recently again reminded of their prime place in the water sector – at the very top.
In this Issue
Caribbean Water and Sewage Association Inc. July-September 2015
Water in the 23 Agenda for Sustainable Development Page 2
CAWASA Secretariat News Page 3
Troubled Water! Page 7
Water is Indeed Life! Page 11
BNTF Funds Saint Lucia Water Page 11
GIZ Assists NAWASA Page 12
Caribbean Braces for Possible Worst Drought Ever! Page 13
CAWASA Congratulates New Guyana Water CEO Page 13
CAWASA E-source Newsletter January - March 2018CAWASA
http://www.cawasa.org - This is the January - March 2018 version of the Caribbean Water and Sewage Association Newsletter.
In this Issue
Caribbean Water and Sewage Association Inc. January to March 2018
Hurricane Maria Recovery in
Dominica
2017: A Year of Accomplishments
and Challengesl – Page 2
CAWASA Secretariat News - Pages 2 - 4
13th High Level Forum of Caribbean Ministers
- Page 5
Successful 2-day Seminar for BWA Staff– Page 5
5th Water Operators’ Conference in Dominica - Page 6
Web-based Operator Certification Exams - Page 7
BWA Personal Water Tank Programme - Page 8
Cayman Islands Laboratory Accreditation
Renewed – Page 9
NAWASA Launches School Community Water
Storage Project - Page 10
NURC Launches Website - Page 11
CaBA Startup Conference 02 - A response to the challenge from the third sectorCaBASupport
Sets the context for the Catchment based Approach, describing the decline in ecosystem functionality and the challenge that still faces the UK in achieving improvements under the Water Framework Directive. Outlines the roles of the new CaBA Partnerships, the National Steering group, and the EA in helping to shape the next round of River Basin Managment Plans, and also in achieving improvements that go beyond WFD.
Ronald T. Green, Ph.D., P.G., F. Paul Bertetti, P.G.,
and Nathanial Toll Geosciences and Engineering Division Southwest Research Institute® Presented on behalf of the Irrigation Panel - TWCA Annual Convention 2015
The importance of groundwater surface water interaction - a case study on Rio...The Texas Network, LLC
Presented by Ronald T. Green, Ph.D., P.G., F. Paul Bertetti, P.G., and Marques Miller
at the Texas Water Conservation Association Conference in The Woodlands, Texas - March 2014
On 17 and 18 June 2020 the EPA held its National Water Event as an online conference.
This year's theme was 'Restoring our waters'.
This years event was free to attend. It was the EPA's largest water event ever, with over 1250 attending.
To everyone who joined us: thanks for attending; thanks for your probing questions; thanks for your passion; thanks for caring about our waters. We can achieve more working together.
Special thanks to all our presenters and the team who worked behind the scenes to make sure this years conference happened.
For science and stories about water quality in Ireland, check out www.catchments.ie
CAWASA Inc. e-Source Magazine July - September 2015 | Caribbean Water And Sew...CAWASA
Caribbean Water Operators provide absolutely essential services across the region. But they are so down-to-earth and close to the
ground that they often go un-noticed. Remembered mainly in cases of emergency, they fix the nation’s water problems so quickly and
efficiently. They come and go in communities affected by water problems and quickly fix pipes and fittings to restore the flow of this
important source, without any waste of time – or water. The region’s water operators are accustomed to going hardly noticed. But they
were recently again reminded of their prime place in the water sector – at the very top.
In this Issue
Caribbean Water and Sewage Association Inc. July-September 2015
Water in the 23 Agenda for Sustainable Development Page 2
CAWASA Secretariat News Page 3
Troubled Water! Page 7
Water is Indeed Life! Page 11
BNTF Funds Saint Lucia Water Page 11
GIZ Assists NAWASA Page 12
Caribbean Braces for Possible Worst Drought Ever! Page 13
CAWASA Congratulates New Guyana Water CEO Page 13
CAWASA E-source Newsletter January - March 2018CAWASA
http://www.cawasa.org - This is the January - March 2018 version of the Caribbean Water and Sewage Association Newsletter.
In this Issue
Caribbean Water and Sewage Association Inc. January to March 2018
Hurricane Maria Recovery in
Dominica
2017: A Year of Accomplishments
and Challengesl – Page 2
CAWASA Secretariat News - Pages 2 - 4
13th High Level Forum of Caribbean Ministers
- Page 5
Successful 2-day Seminar for BWA Staff– Page 5
5th Water Operators’ Conference in Dominica - Page 6
Web-based Operator Certification Exams - Page 7
BWA Personal Water Tank Programme - Page 8
Cayman Islands Laboratory Accreditation
Renewed – Page 9
NAWASA Launches School Community Water
Storage Project - Page 10
NURC Launches Website - Page 11
CaBA Startup Conference 02 - A response to the challenge from the third sectorCaBASupport
Sets the context for the Catchment based Approach, describing the decline in ecosystem functionality and the challenge that still faces the UK in achieving improvements under the Water Framework Directive. Outlines the roles of the new CaBA Partnerships, the National Steering group, and the EA in helping to shape the next round of River Basin Managment Plans, and also in achieving improvements that go beyond WFD.
Flood and drought mitigation - Matt MachielseYourAlberta
Matt, Assistant Deputy Minister with Alberta Environment and Sustainable Resource Development presented at Alberta’s Watershed Management Symposium: Flood and Drought Mitigation. He explained key findings from the Government of Alberta’s flood mitigation engineering studies are presented, along with next steps for major flood mitigation projects.
Stressors, Linkages, Progress, and Lessons Learned from Basin-Wide Planning a...Kim Beidler
Stressors, Linkages, Progress, and Lessons Learned from
Basin-Wide Planning and Implementation for Water Quality and Quantity Restoration and Protection
• Basin Context
• Water Supply
• Water Quality
• 2030 Vision
Breakout Session Slides
Encouraging Urban Green Infrastructure Practices for Climate Resiliency – Jennifer Fish will discuss how Green Infrastructure above the minimum stormwater standards is important to community sustainability. This includes designing for future storm events and better using existing environmental services.
Monday, February 12, 2:30 - 2:55 p.m.
Duke Bitsko - Alewife Stormwater Wetlandbio4climate
Duke Bitsko, landscape architect with Chester Engineers describes a large-scale project he worked on in the Alewife Reservation, transforming a degraded low-quality upland habitat into a constructed stormwater wetland and park. The interdisciplinary team incorporated green infrastructure strategies to create diverse upland and wetland native plant communities.
Presented at the Urban and Suburban Carbon Farming to Reverse Global Warming conference at Harvard University on May 3, 2015, organized by Biodiversity for a Livable Climate.
www.bio4climate.org
The Chesapeake Bay Foundation’s 2014 State of the Bay report presents a mix of good and bad news. The great news: Water quality indicator scores have improved significantly over the 2010 and 2008 scores. The worrisome news: Blue crabs and striped bass are not doing well. The declines in these metrics and in the phosphorus indicator offset the improvements in water quality. Overall, the 2014 score is unchanged from 2012.
Talbot County Clean Water Forum
Presented by Erik Fisher, Chesapeake Bay Foundation
On April 9, 2015, the Chesapeake Bay Foundation, Talbot Preservation Alliance, and the Midshore Riverkeeper Conservancy hosted an overview of pollution reduction challenges and opportunities in Talbot County, Maryland.
A presentation of local water quality conditions and trends was followed by a review and discussion of local pollution sources and practical, cost-effective ways to improve the health of Talbot County's rivers and streams.
For more information about the Talbot County Clean Water Forum, contact Hilary Gibson at 410.543.1999.
(See notes below) Four hundred years ago, the Chesapeake Bay that the English colonists found here was lined with huge oyster reefs that grew up from the bottom in waters both deep and shallow. Those reefs provided the base for much of the life in the Bay and its rivers, from worms and barnacles through mud crabs and tiny fish to big blue crabs and predators like sheepshead, drum, and rockfish (striped bass).
The oyster reefs weren’t as “pretty” (to us humans) as the coral reefs further south, but in terms of ecosystem richness, they were just as important. One key to their strength was their three-dimensional structure, which successive generations built gradually on the shells of their predecessors over several thousands of years. The structures placed the oysters up in the water column, away from gill-choking bottom sediments, where dissolved oxygen was plentiful and currents brought food in the form of algae cells seeking sunlight.
This PowerPoint presentation, developed by the Chesapeake Bay Foundation’s Fisheries Program Director Bill Goldsborough, tells the story of those reefs and what has happened to them over the past four hundred years. It is not a pretty story, but it offers a hopeful conclusion, as we learn more each year about how to restore these essential elements in the Chesapeake ecosystem.
Anglers have as much to gain as anyone in restoring the Chesapeake’s oysters. The presentation closes with suggestions for how to get involved in oyster restoration, and how to incorporate the restoration reefs into your 2015 angling season.
To participate in CBF’s oyster restoration programs in Virginia and Maryland, visit http://www.cbf.org/oysters.
Talbot County Clean Water Forum
Presented by Ray Clarke, Talbot County Department of Public Works
On April 9, 2015, the Chesapeake Bay Foundation, Talbot Preservation Alliance, and the Midshore Riverkeeper Conservancy hosted an overview of pollution reduction challenges and opportunities in Talbot County, Maryland.
A presentation of local water quality conditions and trends was followed by a review and discussion of local pollution sources and practical, cost-effective ways to improve the health of Talbot County's rivers and streams.
For more information about the Talbot County Clean Water Forum, contact Hilary Gibson at 410.543.1999.
Epcon is One of the World's leading Manufacturing Companies.EpconLP
Epcon is One of the World's leading Manufacturing Companies. With over 4000 installations worldwide, EPCON has been pioneering new techniques since 1977 that have become industry standards now. Founded in 1977, Epcon has grown from a one-man operation to a global leader in developing and manufacturing innovative air pollution control technology and industrial heating equipment.
Microbial characterisation and identification, and potability of River Kuywa ...Open Access Research Paper
Water contamination is one of the major causes of water borne diseases worldwide. In Kenya, approximately 43% of people lack access to potable water due to human contamination. River Kuywa water is currently experiencing contamination due to human activities. Its water is widely used for domestic, agricultural, industrial and recreational purposes. This study aimed at characterizing bacteria and fungi in river Kuywa water. Water samples were randomly collected from four sites of the river: site A (Matisi), site B (Ngwelo), site C (Nzoia water pump) and site D (Chalicha), during the dry season (January-March 2018) and wet season (April-July 2018) and were transported to Maseno University Microbiology and plant pathology laboratory for analysis. The characterization and identification of bacteria and fungi were carried out using standard microbiological techniques. Nine bacterial genera and three fungi were identified from Kuywa river water. Clostridium spp., Staphylococcus spp., Enterobacter spp., Streptococcus spp., E. coli, Klebsiella spp., Shigella spp., Proteus spp. and Salmonella spp. Fungi were Fusarium oxysporum, Aspergillus flavus complex and Penicillium species. Wet season recorded highest bacterial and fungal counts (6.61-7.66 and 3.83-6.75cfu/ml) respectively. The results indicated that the river Kuywa water is polluted and therefore unsafe for human consumption before treatment. It is therefore recommended that the communities to ensure that they boil water especially for drinking.
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
Improving the viability of probiotics by encapsulation methods for developmen...Open Access Research Paper
The popularity of functional foods among scientists and common people has been increasing day by day. Awareness and modernization make the consumer think better regarding food and nutrition. Now a day’s individual knows very well about the relation between food consumption and disease prevalence. Humans have a diversity of microbes in the gut that together form the gut microflora. Probiotics are the health-promoting live microbial cells improve host health through gut and brain connection and fighting against harmful bacteria. Bifidobacterium and Lactobacillus are the two bacterial genera which are considered to be probiotic. These good bacteria are facing challenges of viability. There are so many factors such as sensitivity to heat, pH, acidity, osmotic effect, mechanical shear, chemical components, freezing and storage time as well which affects the viability of probiotics in the dairy food matrix as well as in the gut. Multiple efforts have been done in the past and ongoing in present for these beneficial microbial population stability until their destination in the gut. One of a useful technique known as microencapsulation makes the probiotic effective in the diversified conditions and maintain these microbe’s community to the optimum level for achieving targeted benefits. Dairy products are found to be an ideal vehicle for probiotic incorporation. It has been seen that the encapsulated microbial cells show higher viability than the free cells in different processing and storage conditions as well as against bile salts in the gut. They make the food functional when incorporated, without affecting the product sensory characteristics.
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
2. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Non-profit 501(c)3, non-advocacy organization founded
in 1992
Work with watershed groups, local, state and federal
governments
Provide tools to communities to protect lakes, rivers,
streams, and estuaries
20 staff in Ellicott City, MD; Field Offices in
Charlottesville, Richmond, & Leesburg, VA; & Ithaca, NY;
and Philadelphia, PA
www.cwp.org
3. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Welcome and Introductions
Historical Perspective
Today’s Perspective
break
Connecting the VRRM Dots: Quality
lunch
Connecting the VRRM Dots: Quantity
break
Meet the BMPs (Coastal Plain Adaptations)
Design Examples & Discussion
4. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Goal of Today’s Workshop:
Understand the differences (and similarities) between
the old (Part IIC) & the new (Part IIB) criteria;
Become familiar with the new menu of BMPs and their
respective performance credits;
Identify issues and/or specific topics for future training
opportunities
5. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Detailed design instructions for BMPs;
Detailed analysis of life-cycle cost of BMPs;
Computational Hydrology & Hydraulics;
Easy solution for stormwater design on
challenging sites:
• Tidal influenced drainage system;
• High water table;
• Flat terrain.
6. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Be engaged
Ask critical questions
Share your expertise
Respect your colleagues:
7. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Why is it different?
and,
Why do we care?
8. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Flat Terrain
• High water table
• Poorly drained soils
• Very well drained soils
• Highly altered drainage
9. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Shoreline buffer and critical areas cannot be
used for stormwater practices
Dugout ponds intersect with shallow water
table and connect to receiving estuaries
Unique development patterns (waterfront,
marinas, golf courses)
10. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Highway ditches serve as the primary stormwater
receiving and conveyance system;
Heavy seasonal rainfall (hurricanes & Nor’easters)
Historical drainage intended to serve agriculture
Sea level rise
12. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Where is all that water going?
To the nearest waterway — and it is traveling fast.
13. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
The Economic Benefits of Cleaning Up the
Chesapeake
Chesapeake Bay Foundation, 2014
Annual economic benefits derived from the land
and waters of the Chesapeake Bay region
~ $107 billion
Continued/Improved implementation of
multiple targeted programs (Chesapeake Clean
Water Blueprint) are expected to increase the
value 21% (~ $130 billion);
14. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Ecosystem Service Valuation:
Water Flow Regulation;
Air Pollution Treatment;
Food Production;
Water Supply;
Waste Treatment;
Climate Stability;
Aesthetic Value; and
Recreation.
15. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
•• Extreme storms eventsExtreme storms events
•• Population growth & rapidPopulation growth & rapid
developmentdevelopment
•• Wetland, contiguous forest,Wetland, contiguous forest,
& upland habitat preservation& upland habitat preservation
•• Wastewater disposalWastewater disposal
•• Shellfish prohibitionsShellfish prohibitions
•• Harmful algal bloomsHarmful algal blooms
•• Pollution preventionPollution prevention
–– NitrogenNitrogen
–– BacteriaBacteria
•• Maintain waterMaintain water--basedbased
recreationrecreation
Coastal ConcernsCoastal ConcernsCoastal Concerns
Impact to Recreation and Economic Resources:
Shellfish bed closures;
Beach closures;
Decreased fisheries;
Algal blooms
16. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
“the effects of watershed alteration on coastal
resources are poorly understood and inaccessible
to watershed and coastal resource managers.”
(DeVoe and Kleppel, 2006)
Studies suggest a strong negative
relationship between land
development (multiple metrics) and
the biological, physical and
chemical conditions of coastal water
resources
17. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
10% 40%25%
Good
Fair
Poor
Watershed Impervious Cover
StreamQuality
60% 100%
Urban Drainage
Over 200 studies:
• Hydrologic Indicators
• Stream Habitat Indicators
• Water Quality Indicators
• Aquatic Diversity Indicators
18. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Threshold values:
Coastal plain streams: 3.5 – 14%
Tidal creeks: 10 – 30%
Estuariane: 24 – 35%
Coastal Plain Watershed Management; Watershed Protection Techniques Vol. 4; No. 1; 2010
20. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Sustainable Development in the Coastal Plain:
Land use plans should allocate lands to their
most appropriate uses;
Requires knowledge and consideration of
physical constraints;
important natural features and the functions they
provide;
potential hazard areas; and
the capacity of the land to support a given use.
Coastal Plain Watershed Management; Watershed Protection Techniques Vol. 4; No. 1; 2010
23. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
VA Erosion & Sediment Control Program
GC-7
MS-19:
Properties and waterways
downstream of
development shall be
protected from sediment
deposition, erosion and
damage due to . . .
24. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
. . . . Increases in runoff volume, . . .
25. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
. . . . velocity, and peak flow rate of
stormwater runoff . . .
. . . in accordance with the following:
26. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
b.The adequacy of all channels and pipes
shall be verified in the following manner:
(1) 1% rule
the applicant shall demonstrate that the total
drainage area to the point of outfall analysis is
100 times greater than the contributing DA of
the project
27. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
(2) (a) Natural Channels:
2-yr erosion;
2-yr overtopping the banks.
(b) Manmade Channels:
2-yr erosion;
10-yr overtopping the banks.
(c) Pipes and storm sewers:
10-yr capacity
28. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
If existing pipes or channels are not adequate, the
applicant shall:
(1) Improve the channel, or
(2) Improve the pipe system, or
29. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
If existing pipes or channels are not adequate, the
applicant shall (continued):
(3) Develop a site design that does not cause an
increase in the 2-yr peak rate of runoff;
30. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
If existing pipes or channels are not adequate, the
applicant shall (continued):
Or:
(4) “Provide a combination of channel
improvement, stormwater detention, or other
measures satisfactory to the VESCP Authority . . . ”
31. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Assumed C soils; Pre-developed land cover = Woods, good condition
32. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1988 Chesapeake Bay Preservation
Act
(§ 62.1‐44.15:67)
&
The Chesapeake Bay
Preservation Area Designation
and
Management Regulations
(9VAC25-830)
33. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Stormwater BMP Sizing
and
Performance Credits
Performance:
Low to Moderate to High
measured from 0 to 100%
(Nationwide Urban Runoff Program
1979 - ’83)
Sizing:
1st Flush to 2” runoff depth
34. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1998 Amendments to the VA SWM Regulations
Water Quality Compliance:
Performance-Based Criteria; or
• Development Situations 1 thru 4;
• Compliance with Average Land Cover Condition: 16% IC
• Equivalent Annual TP Load = 0.45 lb/ac/yr
Technology Based Criteria
35. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Simple Method: Average Annual Load
𝐿𝑜𝑎𝑑 = 𝑃 × 𝑃𝑗 × 𝑅 𝑣 × 𝐶 × 𝐴 × 2.72/12
P = average annual rainfall depth (inches) = 43 inches (VA)
Pj = fraction of rainfall events that produce runoff = 0.9
Rv = volumetric runoff coefficient = 0.05 + (0.009 × I); I = impervious cover
C = flow-weighted event mean concentration (EMC) of TP = (mg/L) = 0.26 mg/L
A = contributing drainage area (acres)
2.72 = unit conversion factor: L to ft3, mg to lb, and acres to ft2
12 = unit conversion factor: rainfall inches to feet
36. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Treatment Volume & BMP Sizing
𝑊𝑄𝑣 = Water Quality Volume
𝐼𝐶 = Impervious Cover in the contributing
drainage area to the stormwater practice
𝑊𝑄𝑣 = 0.5" × 𝐼𝐶
37. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
* Innovative or alternate BMPs not included in this table may be allowed at
the discretion of the local program administrator or the Department.
38. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Water Quantity Compliance:
Properties and receiving waterways downstream of
any land development project shall be protected
from erosion and damage due to increases in
volume, velocity and peak flow rate of stormwater
runoff in accordance with . . .
39. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Water Quantity Compliance:
Minimum Standard 19 of the ESC Regulations; or
The plan approving authority may determine that
some receiving stream systems require enhanced
criteria to address increased frequency of bankfull
flows and therefore require:
24-hour Extended Detention of the runoff from
the 1-year 24-hour storm
40. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Water Quantity Compliance:
2-yr post back to pre vs 1-yr ED
Moderate development (32% IC):
• > 2 x increase in runoff volume
• 4 to 8 x increased Frequency of bankfull flows;
. . . . significant reduction in stream channel
erosion below facilities designed for 24-hour ED of
the 1-yr frequency runoff (Galli, MWCOG 1992)
41. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Assumed C soils; Pre-developed land cover = Woods, good condition
43. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
What types of BMPs or BMP strategies have
proven to be effective in coastal plain?
45. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
2005 NOIRA: Update Virginia’s Stormwater
Management Regulations:
1) allow for the delegation of the VSMP to localities;
2) develop a framework for the Commonwealth to run
local programs as needed;
3) allow for changes as needed to improve the
administration and implementation; and
4) allow for removal of the out-of-date BMPs (Table 1)
46. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
EPA Performance Standards
• Protect and restore the physical, chemical and
biological integrity of receiving waters;
• Treat flow (volume) as a surrogate for other
pollutants (reference the National Research Council:
Urban Stormwater Management in the United
States);
• Replicate pre-development hydrology:
Infiltrate, evapotranspirate, or reuse the
runoff from the 90th percentile rainfall event
47. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
2007 NOIRA: Replace & clarify the 2005 NOIRA:
1) Amendments, deletions, or additions to Part I
(Definitions, Purpose, and Applicability);
2) Amendments, deletions, or additions to Part II
(Technical Criteria);
3) Amendments, deletions, or additions to Part III (Local
Programs); and
4) Other technical amendments, deletions, or additions
(as may be needed).
48. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Inspector General Report on efforts to restore the
Chesapeake Bay (2007)
• % increase in Impervious cover 5 times that of
population;
• Pollutant load from urban runoff represents the only
increasing source;
• Cost effective solutions dependent on initial site-
specific assessment of topography, soil conditions,
etc.
• Ineffective use of regulatory programs;
49. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
2009 NOIRA:
0.28 lb/ac/yr
52. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Encourage Low Impact Development
Inclusion of land cover type in pollutant and
hydrologic loading factors (good science)
New treatment options with performance credit
breakouts (better science)
RR + PR (EMC) Mass Load Reduction
Step-wise (iterative) simplified compliance
process.
Environmental Site Design
53. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
evapotranspiration:
40-50%
interflow: 20-30%
surface runoff: <1%
54. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
evapotranspiration:
~25%
interflow: 0-30%
surface runoff: ~30%
55. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Research shows:
Extended Filtration mimics the hydrologic characteristics
(meaning stormflow reaching a stream) of an
undeveloped watershed.
Data also indicates that extended filtration releases
water over a much longer period of time than an
undeveloped (agricultural) watershed; and likely a
comparable period of time as a forested watershed.
Hunt et al., NCSU 2010
56. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Runoff Reduction is not just infiltration!
Infiltration
Canopy Interception
Evaporation
Transpiration
Rainwater Harvesting
Extended Filtration
Soil Amendments
58. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Compliance Spreadsheet
59. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Codifies & incentivizes minimization and
avoidance
Goes beyond impervious cover as a water
quality indicator
Utilizes latest BMP research for Total
Performance (Total Mass Load Removal)
Credits total BMP performance
60. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Environmental Site Inventory & Assessment
• Forest conservation
• Suitable soils
• Steep slopes
• Drainage
• Wetlands
• Zero-order streams
• Buffers
• Sensitive areas
• Limits of disturbance
• Computed nutrient loads &
treatment volume
64. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
A 1990 study for the city of Virginia Beach
compared the costs and benefits of conventional
and smart growth development patterns. The
study found:
smart growth pattern resulted in 45% more land
preserved,
45% less in infrastructure costs to the city, and
50% reduction in impervious surface due to
roads
(Siemon, Larsen and Purdy, et al., 1990)
65. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
An Assessment of the Better Site Design Principles
for Communities Implementing Virginia’s
Chesapeake Bay Preservation Act (CWP, 2000)
• 16 Model Development Principles
• 4 development projects
• Average 28% reduction in Total Infrastructure Costs
(47%; 15%; 49%; NC)
66. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
The Economic Benefits of Watershed Protection
(CWP, 2001)
1. Watershed Planning
2. Land Conservation
3. Aquatic Buffers
4. Better Site Design
5. Erosion & Sediment Control
6. Stormwater Treatment
7. Non-Stormwater Discharges
8. Watershed Stewardship
67.
68. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1. Site Data Input:
• Site Land cover
• Site level Treatment Volume
(Tv)
• Site level pollutant loads and
Removal Requirement
2. Drainage Area Inputs:
• DA Land Cover
• TvBMP (used for BMP sizing)
• Area treated check
• DA pollutant removal
1. Site Data
Input
2. Drainage
Area Inputs
4. Channel/Flood Protection
Check
3. Water Quality
Check
5. Summary
Print-out
69. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Volumetric Runoff Coefficients
• Land Cover (acres) by HSG
• Definitions Provided in
Guidance
Composite Site Rv
Post-Dev Tv
Pollutant Load (TP & TN)
Total Load Reduction Reqd.
Weighted (by HSG) Rv for Forest, Turf, & Imp
70. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
15 Acres
25 ½ acre lots
Drainage Area Land Cover (Acres)
Land Cover Total
½ acre lots
Total
¼ acre lots
Forest 0.87 4.31
Turf 8.32 5.26
Impervious 2.26 1.88
15 Acres
25 ¼ acre lots
Drainage Area Water Quality Requirements
Total
½ acre lots
Total
¼ acre lots
Post-Dev Treatment Vol 14,452 ft3 11,198 ft3
Post-Dev TP Load 9.08 lb/yr 7.04 lb/yr
Pollutant Removal Reqd. 4.39 lb/yr 2.34 lb/yr
73. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Finger printing on large
lot construction:
Save trees, soil, etc.
Finger-printing subdivision
construction:
narrow streets; shorter setbacks, etc.
74. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Reduced runoff
coefficients for
undisturbed pervious
areas;
• Increased runoff
coefficients for
impacted soils &
managed turf;
75. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Cover HSG A HSG B HSG C HSG D
Forest/Open 0.02 0.03 0.04 0.05
Managed Turf /
Disturbed Soil
0.15 0.20 0.22 0.25
Impervious Cover 0.95 0.95 0.95 0.95
1 Center for Watershed Protection – Technical Memorandum: The Runoff
Reduction Method; 4/18/08
Pitt et al (2005), Lichter and Lindsey (1994), Schueler (2001a, 2001b, 1987),
Legg et al (1996), Pitt et al (1999), and Cappiella et al (2005)
76. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Codifies & incentivizes minimization and
avoidance
Goes beyond impervious cover as a
water quality indicator
Utilizes latest BMP research for Total
Performance (Total Mass Load Removal)
Credits total BMP performance
77. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Impacts from grading and compaction of
soils
78. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Impacts from turf management activities
79. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Forest & Open Space:
• Undisturbed portions of residential development;
• Open space left in natural vegetated state that will
not be managed as turf (regular mowing, fertilized,
etc.); includes utility ROW’s with periodic bush-
hogging;
• Surface area of BMPs that have vegetative cover
(not wet ponds, green roof, permeable pavement);
Managed Turf
Impervious Cover
80. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Simple Method – Average Annual Load:
𝐿𝑜𝑎𝑑 = 𝑃 × 𝑃𝑗 × 𝑅 𝑣 × 𝐶 × 𝐴 × 2.72/12
P = average annual rainfall depth (inches) = 43 inches (VA)
Pj = fraction of rainfall events that produce runoff = 0.9
Rv = volumetric runoff coefficient = 0.05 + (0.009 × I); I = impervious cover
C = flow-weighted event mean concentration (EMC) of TP = (mg/L) = 0.26 mg/L
A = contributing drainage area (acres)
2.72 = unit conversion factor: L to ft3, mg to lb, and acres to ft2
12 = unit conversion factor: rainfall inches to feet
𝐿 = 𝑃 × 𝑃𝑖 × 𝑅𝑣 𝑐𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑒 × 𝐶 × 𝐴 × 2.72 12
𝑅𝑣 𝑐𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑒 = 𝑅𝑣𝐼 × %𝐼 + 𝑅𝑣 𝑇 × %𝑇 + 𝑅𝑣 𝐹 × %𝐹
81. New Rules (Part IIB)
• C = 0.26 mg/l
From:
Runoff Reduction Method
Technical Memorandum,
April 2008
𝐿 = 𝑃 × 𝑃𝑖 × 𝑅𝑣 𝑐𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑒 × 𝐶 × 𝐴 × 2.72 12
Center for Watershed Protection
83. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1. Weighted average soil cover derived from STATSGO state-wide soils database soil breakdown for VA outside of the
Chesapeake Bay Watershed.
2. Schueler, T., Fraley-McNeal, L., and Capiella, K. “Is Impervious Cover Still
Important? Review of Recent Research” Journal of Hydrologic Engineering, April 2009
1
2
𝐿 = 𝑃 × 𝑃𝑖 × 𝑅𝑣 𝑐𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑒 × 𝐶 × 𝐴 × 2.72 12
84. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
TvBMP = Design Treatment Volume from contributing
drainage area to stormwater practice (does not include
remaining runoff from upstream practices)
P = 90th Percentile rainfall depth = 1”
Rvcomposite = Composite runoff coefficient
A = Direct contributing drainage area to the
stormwater practice
𝑇𝑣 𝐵𝑀𝑃 =
𝑃 × 𝑅𝑣 𝑐𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑒 × 𝐴
12
85. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Washington Reagan Airport
0
1
2
3
4
5
6
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Precipitation Event Percentile
PrecipitationDepth(inches)
90th Percentile rainfall depth
1” annual average: Washington Reagan Airport, Richmond Airport, Harrisonburg, Lynchburg, Bristol
86. Using the 90th percentile rainfall depth translates to
an annual average reduction
• Represents average over all storms and not individual
single-event modeled storms
• Oversizing practice does not necessarily provide for
increase in “annual” RR or PR performance
• Oversizing can help meet quantity control storage
requirements when modeled on single event basis
87. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
0
0.25
0.5
0.75
1
Load(lb/ac/yr)
Required Level
of Treatment
Allowable Load
(lb/ac/yr)
Part II C
Requirements
Part II B
Requirements
Required
Treatment
0.45
0.41
88. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Pollutant Removal
Practices
Minimization/ESDRunoff Reduction Practices
89. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Codifies & incentivizes minimization and
avoidance
Goes beyond impervious cover as a water
quality indicator
Utilizes latest BMP research for Total
Performance (Total Mass Load Removal)
Credits total BMP performance
90. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Total BMP Performance:
Runoff Reduction Reported Performance:
𝑹𝒖𝒏𝒐𝒇𝒇 𝑽𝒐𝒍 𝑰𝑵 𝒗𝒔 𝑹𝒖𝒏𝒐𝒇𝒇 𝑽𝒐𝒍 𝑶𝑼𝑻
+
Pollutant Removal Reported Performance:
𝑬𝑴𝑪 𝑰𝑵 𝒗𝒔 𝑬𝑴𝑪 𝑶𝑼𝑻
=
Total BMP Performance (reported as Load Reduction):
𝑽𝒐𝒍 𝑰𝑵 × 𝑬𝑴𝑪 𝑰𝑵 𝒗𝒔 𝑽𝒐𝒍 𝑶𝑼𝑻 𝑬𝑴𝑪 𝑶𝑼𝑻
Center for Watershed
91. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Runoff Reduction (RR) and Pollutant Removal (PR):
• Allows for reductions beyond irreducible
concentrations by reducing the volume;
• Provides for maximum performance through a
“Treatment Train” approach including non-structural
practices
92. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Bioretention, Infiltration, Dry
Swales, Soil Amendments,
disconnection, and Related
Practices Reduce Runoff
Volumes by 50 to 90%
Wet Ponds, ED Ponds and
Constructed Wetlands and
Filters Reduce Runoff
Volumes by zero to 10%
94. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
BMP
1,000,000 liters of
stormwater
(multiple storm
events)
100 mg/L
pollutant
(average)
1,000,000 liters of
stormwater
(multiple storm
events)
50 mg/L
of pollutant
(average)
No volume reduction, only EMC reduction
100 kg
Total
pollutant
load
50 kg
Total
pollutant
load
SOURCE: VA DEQ, 2013
50% PR
95. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
100 mg/L of
pollutant
(average)
500,000 liters of
stormwater
(multiple storm
events)
50 mg/L
pollutants
(average)
Total Performance = 75% load reduction!
25 kg
Total
pollutant
load
BMP
100 kg
Total
pollutant
load
SOURCE: VA DEQ, 2013 (CORRECTED)
1,000,000 liters of
stormwater
(multiple storm
events)
50% RR
50% PR
+
96. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
The VRRM Technical Memo documented the
performance of BMPs:
RR performance more consistent than PR performance;
Nutrient PR in stormwater BMPs is notoriously
inconsistent;
RR rates are an annual average based on the individual
study site water balance.
The recommended rates are conservative estimates
The RR rates in the regulations are dependent on
meeting Level 1 or Level 2 criteria.
97. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Codifies & incentivizes minimization and
avoidance
Goes beyond impervious cover as a water
quality indicator
Utilizes latest BMP research for Total
Performance (Total Mass Load Removal)
Credits total BMP performance
98. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Level 1 standard features included in all designs:
• Function;
• Safety;
• Appearance;
• Safe conveyance;
• Performance longevity
• Maintenance
99. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Level 2 design enhancements for increased RR, PR or
both:
• Increased Tv sizing (by a factor of 1.1, 1.25 or 1.5
times the Tv);
• Enhanced design geometry;
• Vegetative condition;
• Multiple cells;
• Multiple treatment pathways; and Other bells and
whistles, e.g., increased pretreatment, increased
media depth, etc.
100. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Comparative BMP
Level 1
& Level 2
Performance
101. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Consider guidance to standardize Process Diagrams to
track volume and load through complex treatment trains
102. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Allow for compliance on high density sites;
Provide flexibility on small/tight sites by allowing
multiple smaller BMPs to treat stormwater near the
source;
• as the drainage area incrementally increases (with each RR
practice);
• the RR practices incrementally reduce the runoff volume
and TvBMP,
• each successive BMP is not sized on the entire upstream
drainage area;
• Rather, the BMP is sized by the TvBMP from the directly
contributing drainage area + any remaining runoff from
upstream RR practices.
103. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Level 1 Design (RR 40 TP: 25 ) Level 2 Design (RR: 80 TP: 50)
Sizing (Section 6.1):
TvBMP = [(1)(Rv)(A) / 12] + any remaining
volume from upstream BMP
Sizing (Section 6.1):
TvBMP = [(1.25)(Rv)(A) / 12] + any
remaining volume from upstream BMP
Design Summary Table BMP Design Specification
No. 9: Bioretention
104. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Project Graphic Courtesy of Geosyntec
19.8 acre single Family Subdivision
2.2 acres of R.O.W.
34 lots (avg lot size = ½ acre)
105. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Turf = 12.09
Imp = 7.71
Area Total = 19.8 acres
Site Rv = 0.50
Post Dev Tv = 0.83 ac-ft
Post Dev TP Load = 22.77 lb/yr
Load Reduction Required = 14.65 lb/yr
Site Data Tab
Site Avg BMP Eff. = 14.65/22.77 x 100 = 65%
106. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Credit Area (acres) to
Wet Pond Level 2:
Imp = 7.71 ac
Turf = 12.09 ac
TP Removed = 17.06 lb/yr
0 Runoff Reduction
Area Check: OK
Drainage Area Tab
Remaining Runoff &
TP load
107. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Runoff Reduction = 0
TP Reduction = 17.06 lb/yr
Area Check: OK
108. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1, 2, and 10-year
storm rainfall depths
CN = 83
1, 2, and 10-year volume
(RV) measured in
watershed inches =
RV1 = 1.28 inches
RV2 = 1.76 inches
RV10 = 3.30 inches
No RR
No CN Adjustment!
No volume
reduction
111. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Channel Protection:
Concentrated stormwater flow shall be
released in to a stormwater conveyance
system:
Photo: Williamsburg Environmental Group
Manmade Stormwater
Conveyance System
Restored Stormwater
Conveyance System
Natural Stormwater
Conveyance System
112. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Goals:
• Establish “balance” exerted by pre- and post-
developed 1-yr peak stormwater discharge;
• Incentivize Better Site Design (and volume
reduction);
• Keep it Simple
(Qpeak*Vol)pre (Qpeak*Vol)post
113. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Simple “balance” offsets increase in volume and
peak flow of developed condition hydrology
Post-development
runoff volume increases
Allowable discharge
decreases
114. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Energy Balance
Post (Vol1-yr * Peak Q1-yr) ≤ Pre (Vol1-yr * Peak Q1-yr)
re-written:
IF = Improvement Factor:
(0.8 for sites > 1 acre or 0.9 for sites ≤ 1 acre)
𝑞1𝑝𝑜𝑠𝑡 ≤ 𝑞1𝑝𝑟𝑒
𝑃𝑟𝑒 𝑉𝑜𝑙1
𝑃𝑜𝑠𝑡 𝑉𝑜𝑙1
𝐼𝐹
115. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Use VRRM Spreadsheet to calculate the volume
reduction with a double credit:
• Reduced Volpost1 for Energy Balance Equation; and
• Reduced Curve Number (CN) for computing the
q1post
𝑞1𝑝𝑜𝑠𝑡 ≤ 𝑞1𝑝𝑟𝑒
𝑃𝑟𝑒 𝑉𝑜𝑙1
𝑃𝑜𝑠𝑡 𝑉𝑜𝑙1
𝐼𝐹
Must consider the pre- and post- condition drainage areas!
116. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Roadway
Project Drainage
Area
Residential
Lots
Project Graphic Courtesy of Geosyntec
Typical subdivision development:
117. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
NEW PERVIOUS PAVEMENT
MANAGED TURF
BIORETENTION CELLS
RESIDENTIAL LOTS
Project Graphic Courtesy of Geosyntec
NEW PERVIOUS PAVEMENT
MANAGED TURF
BIORETENTION CELLS
RESIDENTIAL LOTS
ROOFTOP DISCONNECTION
118. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Same as traditional scenario, but with:
• Wet Pond area partially converted
from ‘Impervious Cover’ to
‘Managed Turf’
• BMP areas converted from
‘Managed Turf’ to ‘Forest/Open
Space’
Slight change in Tv, TP Load,
and Reduction Requirement
Center for Watershed 118
119. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
NEW PERVIOUS PAVEMENT
MANAGED TURF
BIORETENTION CELLS
RESIDENTIAL LOTS
Project Graphic Courtesy of Geosyntec
NEW PERVIOUS PAVEMENT
MANAGED TURF
BIORETENTION CELLS
RESIDENTIAL LOTS
ROOFTOP DISCONNECTION
120. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
2
4
34
33
32
3
1
6
7
5
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
No. 1 Bio L2
No. 2 Bio L2
No. 18 Bio L2
?
121. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Aggregated Credit Area to
Simple Disconnection = 5 ac
Runoff Reduction = 4,311 ft3
Runoff Remaining = 12,932 ft3
Downstream Treatment: Bioretention L2
Load Reduction = 2.71 lb
Load Remaining = 8.12 lb
122. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Credit Area (Direct Runoff) to
Bioretention Level 2:
1.89 ac Impervious
5.0 ac Turf
Volume from upstream RR practice:
12,932 ft3
Runoff Reduction = 18,754 ft3
Runoff Remaining = 4,689 ft3
Load Reduction = 2.71 lb
Load Remaining = 8.12 lb
Load from upstream RR practice:
8.12 lb
123. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Area Check - OK
Runoff Reduction Achieved = 23,065 ft3
TP Load Reduction Achieved = 15.96 lb
124. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1, 2, and 10-year
storm rainfall depths
1, 2, and 10-year volume (RV)
reduction =
RV1 = 1.28” 0.96”
CN1 83 77
RV2 = 1.76” 1.44”
CN2 83 78
RV10 = 3.30” 2.98”
CN10 83 80
Volume Reduction = 23,065 ft3
125. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Original design:
• No Volume Reduction;
• Treat 100% of the site (19.8 ac) with Wet Pond Level 2
• Compliance: exceed reqmt. by 2.4 lb/yr
RR Design:
• Treat 11.9 acres
• Compliance: exceed reqmt. by 2.2 lb/yr
• No wet pond Reqd (for water quality)
• Reduce 23,065 ft3 volume (from site Tv = 34,816 ft3)
• Reduce 1-yr CN from 83 to 77
126. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Use VRRM Spreadsheet to calculate the volume
reduction with a double credit:
• Reduced Volpost1 for Energy Balance Equation; and
• Reduced Curve Number (CN) for computing the
q1post
𝑞1𝑝𝑜𝑠𝑡 ≤ 𝑞1𝑝𝑟𝑒
𝑃𝑟𝑒 𝑉𝑜𝑙1
𝑃𝑜𝑠𝑡 𝑉𝑜𝑙1
𝐼𝐹
Must consider the pre- and post- condition drainage areas!
127. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Project Graphic Courtesy of Geosyntec
NEW PERVIOUS PAVEMENT
MANAGED TURF
BIORETENTION CELLS
RESIDENTIAL LOTS
ROOFTOP DISCONNECTION
128. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
2
4
34
33
32
3
1
6
7
5
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
Disconnection
No. 1 Bio L2
No. 2 Bio L2
No. 18 Bio L2
??
129. Challenge:
Provide quantity “credit” for distributed retention
practices
Avoid Complex routing/modeling of multiple practices,
yet simulate single event modeling
Allow designers to target volume as primary metric
(quantity and quality)
Various methods explored by VA TAC
130. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Simplifying Assumptions:
• Assume retention is uniformly distributed if
considering multiple features or sub-areas;
• Assume negligible discharge from under-drains
(if any)
131. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
5 Methods Considered:
1. Hydrograph Truncation
2. Hydrograph Scalar Multiplication
3. Precipitation Adjustment
4. Runoff Adjustment
5. Curve Number Adjustment
Excerpted from work by Paul R. Koch, Ph.D., P.E.
132. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
0%
20%
40%
60%
80%
100%
0% 20% 40% 60% 80% 100%
Volume Stored, as Percent of Total Runoff
PercentofRunoffPeakRemaining
R_trunc
R_as_P
R_as_Q
CN_adj
Scalar
Method of
Analysis
CN Adjustment
Excerpted from work by Paul R. Koch, Ph.D., P.E.
133. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Runoff Depth Equations (TR-55):
Where:
Q = runoff depth (in)
P = precipitation depth (in)
S = potential maximum retention after runoff begins
Ia = initial abstraction, volume filled before runoff begins.
𝑄 =
𝑃 − 𝐼 𝑎
2
𝑃 − 𝐼 𝑎 + 𝑆
𝐼 𝑎 = 0.2𝑆 𝑆 =
1000
𝐶𝑁
− 10
Eq. 2-1:
Eq. 2-2: Eq. 2-4:
134. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Step 3: 1.28” runoff
Step 1: 2.8” rainfallStep 4: Adjust For
Retention (-0.32”)
Step 5: Adjusted CN ~ 77
Step 2: Original CN = 83
135. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1, 2, and 10-year
storm rainfall depths
1, 2, and 10-year volume (RV)
reduction =
RV1 = 1.28” 0.96”
CN1 83 77
RV2 = 1.76” 1.44”
CN2 83 78
RV10 = 3.30” 2.98”
CN10 83 80
Volume Reduction = 23,065 ft3
136. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
One-Year Storm Hydrology Summary: 19.8 acres
Pre-
Developed
Post-
Developed no
RR
Post-
Developed
with RR
Runoff Curve Number 71 83 77
Runoff Volume (RV) 0.62 in 1.28 in 0.96 in
Runoff Volume 1.02 ac-ft. 2.11 ac-ft. 1.58 ac-ft.
Peak Discharge (q1) 9 cfs 39 cfs 27 cfs
Post Developed EB Allowed Peak
Discharge (cfs)
3.5 cfs 4.7 cfs
Storage Volume Reqd. (ac-ft) 1.16 ac-ft.* 0.76 ac-ft.*
34% Reduction in required 1-yr EB Storage Volume
137. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
No RR shown; 34% reduction in volume!
138. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Slight increase in allowable release w/RR
139. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
St. Paul’s Boulevard, City of Norfolk, VA
140. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
< 1 ac of land disturbance: 10% load reduction
≥ 1 ac of disturbance: 20% load reduction
Increase in impervious cover from existing:
• New impervious acreage is managed as new
development (0.41 lb/ac/yr);
• Remainder of site is managed to a 10% or 20%
reduction (as required).
• Definition of site = area of land disturbance
143. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Virginia Stormwater Management Handbook Appendix
6C: Stormwater Design in the Coastal Plain
• Chesapeake Stormwater Network Technical Bulletin
No. 2 (v1.0): Stormwater Design in the Coastal Plain
• HRPDC: Land & Water Quality Protection Phase II
Discouraged BMPs
• Center for Watershed Protection: Watershed
Protection Techniques Vol.4, No. 1, 2010
144. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Maximize on-site micro-practices such as:
• Filter Strips;
• Buffers (reforestation),
• Simple Disconnection;
• Alternative Disconnection
— cisterns,
— dry wells,
— rain gardens, &
— compost amended filter path;
145. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Promote de-nitrification (create adjacent
anaerobic and aerobic zones);
• Avoid infiltration in areas with high water table;
• Utilize native plants;
• Create a rooftop to buffer in-line treatment
train; and
• Relax some design criteria to keep practice
depths shallow!
146. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Maximum bacteria removal:
— long residence time and light exposure for coliform
die off;
— Reduce turf around open water to discourage
geese and waterfowl;
— Use shallow wetlands and benches to create
natural micro-predators;
— Minimize resuspension of bottom sediments
147. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1. Preferred BMPs
2. Accepted BMPs
3. Discouraged BMPs
148. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
1. Widespread feasibility in the coastal plain
2. High runoff reduction capacity
3. Moderate to high removal of nitrogen and
bacteria
4. Low mosquito breeding capability when
installed and maintained properly
Preferred means the practice does well on at least three
factors;
Discouraged does not mean prohibited; rather it suggests
ruling out an alternative preferred practice first
149. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Preferred Accepted Discouraged
Constructed Wetland Wet Ponds
Large Scale
Infiltration
Shallow Bioretention
& Dry Swales
Small-scale
Infiltration
Dry ED ponds
Wet Swale Green Roofs Grass Channels
Rain Tanks/Cisterns
Soil Compost
Amendments
Roof Disconnection &
Filter Strips
Sand Filter
Permeable Pavers
150. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Coastal plain research places wet ponds in 2
general groups:
1. Standard ponds: do not meet criteria and have
low to negative nutrient removal performance;
2. Enhanced ponds: performed much better
resulting from design features:
• geometry: L:W ratio; multiple cells;
• macrophytes and other wetland characteristics
(wetland cells, benches, etc.);
• Extended detention time of incoming runoff;
151. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
James River Basin BMP type (n=3112)
43%
17%
14%
12%
7%
2%
2%
2%
1%
0%
0%
0%
0%
0%
0%
0% 10% 20% 30% 40% 50%
Wet Pond
Pond, Unidentified Detention
Grass Channel
Infiltration
Other
Pond, Water Quality Detention
Proprietary Device
Bioretention
Constructed Wetland
Underground Storage
Filter Practice
Permeable Pavement
Dry Swale
Level Spreader
Wet Swale
• Hirschman and Woodworth, 2009; and
• Literature Synthesis of SC and NC studies; Drescher at al, 2007)
152. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Review of coastal plain wet ponds (as installed &
maintained):
• A large number fail to meet basic (minimum)
design criteria (and enhanced guidelines);
• Many exhibited functional problems relating to
a lack of maintenance (sediment deposition,
excessive plant growth, trees on embankment);
• worst performing were small (pocket style) with
a small contributing drainage area (squeezed
onto site)
153. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Key design drivers:
• Eutrophication: function of nutrient input and
residence time (defined as pool vol/annual runoff
input); and
• Depth of the anoxic zone (which increases the
nutrient release from the bottom sediments).
154. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
• Expected nutrient removal rates are slightly reduced in
the coastal plain due to the influence of groundwater,
• Certain design features are essential to achieving
reduction (multiple cells, benches, flow path, etc.)
• Certain design features can enhance performance
(landscaping, bubblers & fountains, floating wetlands)
can improve their function.
• Wet ponds can produce and or export harmful algal
blooms if they interact with brackish ground or surface
waters
156. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Runoff Reduction = 0
TP Reduction = 17.06 lb/yr
Area Check: OK
New Level 2 TP reduction Credit (65%)
= 14.8 (coastal plain):
Congratulations!!
157. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
* Includes: multi-cell design, sediment forebays, pool geometry (L:W = 2:1)
** Aquatic Bench
Part IIC Retention Basin
WQv
Pool Volume
(ac-ft.)
TP Reduction
Credit
Retention Basin I*
0.475 ac-ft.
(3x) = 1.425 40%
Retention Basin II* (4x) = 1.90 50%
Retention Basin III** (4x) = 1.90 65%
Part IIB Retention Basin
Tv
Pool Volume
(ac-ft.)
TP Reduction
Credit
Retention Basin L1*
1.180 ac-ft.
1.180 50% (45%)
Retention Basin L2** 1.77 75% (65%)
* Includes: safety bench, aquatic bench, sediment forebays, L:W = 2:1
** Multi-cell design, 10% surface area wetland; 50% of Tv can be in ED above
normal pool, L:W = 3:1;
161. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Application of a maximum impervious area per
disconnection:
• Alternate Disconnection; or
• Vegetated Filter Strips
165. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Key Design Consideration: Nomenclature!
Conserved Open Space
Width
Width
Length
166. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Key Design Considerations:
• Establish or maintain good vegetative cover;
• Establish and maintain sheet flow
• Thick no-mow (low
maintenance)
vegetation.
http://www.clemson.edu/extension
167. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Key Design Consideration:
Engineered Level Spreader (ELS) combined with forebay,
energy dissipator, rigid lip, & gravel diaphragm
Photo: R. Winston; BAE Stormwater Engineering Group, NCSU
169. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
‒Vegetated Filter Strips
‒Rainwater Harvesting
‒Green Roofs
‒TREES!!!!
SWM Benefits of Trees (D. Wible, CH2MHILL)
170. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
“Water Spreading”
Trees of the poplar,
cottonwood, and willow
family have been shown
to draw as much as 200
gallons of water per day
(EPA, Introduction to
Phytoremediation)
173. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Stormwater BMP Enhancements
174. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Photo Credit: Jeremy Balousek, P.E., Dane County, WI Land and
Water Resources Department
Photo Credit: Richard McLaughlin, Ph.D., North Carolina State
University
Soil Restoration
177. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
S. Day, S. Dickenson; Virginia Tech Departments of Forestry and Horticulture
Managing
Stormwater for
Urban
Sustainability
Using Trees and
Structural Soils
178. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Susan Downing Day
&
Sarah B. Dickenson
Virginia Tech
Departments of Forestry and Horticulture
179. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Type of pavement materials
Pervious Concrete Porous Asphalt
Permeable
Interlocking
Concrete Pavers
Concrete Grid Pavers
Pervious Composites Permeable Rubber
Overlays
180. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Level 1
Level 2 (infiltration)
Level 2 (infiltration sump)
181. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Design Option: ‘Upturned Elbow’
Anaerobic Zone for denitrification
182. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Pavement Structural Design
• Thickness of permeable
pavement and reservoir
layer must be sized to
support structural loads
• Primary design elements:
– Anticipated traffic loads;
– Underlying soil properties;
– Surface and bedding strength
coefficients
183. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Key Design Consideration: External Drainage Areas
In all cases, external
drainage areas should
be limited to
impervious surfaces to
reduce potential
sediment loading
184. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Key Design Consideration: Maintenance
186. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Annual runoff reduction volume credit only
awarded for dedicated year-round water
drawdown/demand
Laundry washing Vehicle washingToilet flushing
187. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Street Sweepers
Vactor Trucks
Public Works
188. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Seasonal uses must be supplemented with runoff
reduction drawdown practice
Irrigation
Cooling tower make-up water
189. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Location
Roof Area
Indoor
Demand
190. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Secondary
Drawdown
Cooling
Towers
Seasonal
Irrigation
Seasonal with or
w/o smart control
191. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Additional Daily
Use:
• Vehicle wash
• Street Sweepers
• Vactor Truck
• Etc.with or
Additional Sources
of water
Losses
192. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Without a Smart Control With a Smart Control
Cumulative Daily Water Use
and Equivalent Year Round Use
193. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Overflow (and dry)
Volume & Days
(all storms)
Typical (rain)
Year
194. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
7,000 Gallon Cistern Water Levels and Precipitation during a
Normal Rainfall Year
195. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Annual Runoff
Reduction Credit
(based on cistern
size)
196. Stormwater in the Coastal Plain – Virginia Beach, December 3, 2014
Tank Design 2: Storage Associated with Treatment, Channel Protection and Flood Volume
Tank Design 1: Storage Associated with Treatment Volume (Tv) only