Looking beyond 2010… Offsetting Nutrient Loads in the Face of Urban Growth. WRTC Meeting May 11, 2006. Condensed from Bay Program Reevaluation Workshop Presentation September 21, 2005. Ted Graham, Chair Land, Growth, and Stewardship Subcommittee. Major Points. - PowerPoint PPT Presentation
8
Looking beyond 2010… Looking beyond 2010… Offsetting Nutrient Loads in the Face of Urban Offsetting Nutrient Loads in the Face of Urban Growth Growth Condensed from Bay Program Reevaluation Condensed from Bay Program Reevaluation Workshop Presentation Workshop Presentation September 21, 2005 September 21, 2005 Ted Graham, Chair Ted Graham, Chair Land, Growth, and Stewardship Land, Growth, and Stewardship Subcommittee Subcommittee WRTC Meeting WRTC Meeting May 11, 2006 May 11, 2006
Transcript
Looking beyond 2010…Looking beyond 2010…
Offsetting Nutrient Loads in the Face of Urban GrowthOffsetting Nutrient Loads in the Face of Urban Growth
Condensed from Bay Program Reevaluation Condensed from Bay Program Reevaluation Workshop PresentationWorkshop Presentation
September 21, 2005September 21, 2005
Ted Graham, ChairTed Graham, ChairLand, Growth, and Stewardship SubcommitteeLand, Growth, and Stewardship Subcommittee
WRTC MeetingWRTC MeetingMay 11, 2006May 11, 2006
Major Points
2. Urban development, including wastewater, contributes more nutrients to the Bay than agriculture.
3. The C2K goal to achieve and maintain water quality can only be met if new urban loads are offset.
4. Projections of urban development and loads beyond 2010 are needed to estimate the scale of required offsets.
1. Urban development is the fastest growing source of nutrients to the Bay.
5. Analysis is needed to determine what constitutes an effective offset program.
6. COG member/WRTC input is warranted here, both for wastewater & urban stormwater sectors
“If recent trends continue, the area of developed land in the (Bay) watershed will increase by more than 60% by 2030”
~ “Chesapeake Futures: Choices for the 21st Century”, STAC 2003.
Between 1990 and 2000:• population increased 8%• impervious surfaces increased 41%
Forecasting Future Land Use
Because:
• Smaller family size
• Bigger houses
• Larger commercial and retail parking lots
Nitrogen Loads to the Chesapeake Bay Watershed (Total Loads – Overall Program Focus Excluding Overall Growth)
108.2
48.8
61.2
12.2
0
20
40
60
80
100
120
Agriculture Urban/ Suburban Runoff Point Source Septic
(mill
ion
lbs/
year
)
Total loads to the Chesapeake Bay in million pounds per year answer questions concerning overall program focus.
When “urban/suburban” total loads consider only the stormwater runoff from the land area, the question of “urban/suburban” loads versus agricultural loads treats population as a given and speaks to land conversion.
In this case for nitrogen, total agricultural loads exceed urban/suburban runoff – looking at the scale of the Chesapeake Bay watershed as a whole.
Urban Development May Impact Restoration Progress:Flow-Adjusted Trend in Total Nitrogen
DRAFT
Nitrogen Loads to the Chesapeake Bay Watershed (Total Loads – Overall Program Focus Excluding Overall Growth)
108.2
48.8
61.2
12.2
0
20
40
60
80
100
120
Agriculture Urban/ Suburban Runoff Point Source Septic
(mill
ion
lbs/
year
)
Total loads to the Chesapeake Bay in million pounds per year answer questions concerning overall program focus.
When “urban/suburban” total loads consider only the stormwater runoff from the land area, the question of “urban/suburban” loads versus agricultural loads treats population as a given and speaks to land conversion.
In this case for nitrogen, total agricultural loads exceed urban/suburban runoff – looking at the scale of the Chesapeake Bay watershed as a whole.
Recommendations
2. LGSS be tasked with revising the growth allocation models to drive the Phase V Watershed Model.
3. LGSS and NSC be tasked with estimating 2030 nutrient projections by major watershed.
4. LGSS and NSC, in consultation with LGAC, be tasked with defining the framework of an urban development offset program.
1. LGSS be tasked with preparing 2030 development projections.
TIMING: July 17, 2006 – 2030 Land Use Projection Worksession October 2006 – September 2007 - Alternative Growth Scenarios (Urban, Wastewater, Agriculture, Forest) January 2007 – WS Model Runs of 3-5 alternative scenarios
