Title: Is it necessary to augment water supply to meet increasing water demands in Coventry and West Greenw
1Is it necessary to augment water supply to meet
increasing water demands in Coventry and West
Greenwich, RI?
- the role of urban
planning in water supply
management - erin bray
- brown university
- masters candidate
- may, 2005
2New Growth in Coventry and West Greenwich
- 1950 - 2000, Coventry has grown by 241, West
Greenwich has grown by 500. - Kent County Water Authority states limits to
water supply - Centre of New England Business Park in Coventry
and others
Watershed Basins Pawcatuck Pawtuxet
3Water Supply Augmentation?
KCWA Mishnock Wellfield
North Branch Pawtuxet
Quinebaug River Basin
Centre of New England
South Branch Pawtuxet
Upper Wood
Usquepaug-Queen
Big River Management Area
I-95
4Precautionary Aggressive Buildout Scenarios
based on Existing Zoning
Is there enough water available in the subbasins
of Coventry and West Greenwich to meet future
demands at buildout?
5FUTURE ZONING OF UNBUILT AREAS
50 of Coventry is currently undeveloped
15,000-20,000 acres 35 of West Greenwich is
currently undeveloped 9,000-13,000 acres
6When will buildout occur?
West Greenwich averages 39 building
permits/year New Cap 32
Coventry averages 129 building permits/year
COVENTRY 41
- 56 years 2045 -
2060 WEST GREENWICH 101 -139
years 2105 2143
7What difference does this make with respect to
water demand?
- Towns must understand the impacts that their
regulations and ordinances have on water supply - Regional planning is at the root of determining
new water demands - Zoning occurs as if water supply can meet
anticipated needs - New developments such as Centre of New England
are given Master Plan approval without securing
adequate water - ? ? ?
- USGS Water Use and Availability
- 1995-99 is baseline reports total use at 5.28
Mgal/d
8Future Residential Water Demand
1995 2150
Gallons Per Day
Total Residential
Aggressive
Precautionary
Aggressive
Precautionary
9Future Commercial Industrial Water Demand
Gallons Per Day
Total Commercial Industrial
West Greenwich Industrial
Coventry Industrial
Centre of New England
Coventry Commercial
West Greenwich Commercial
Amgen
1014.4 Mgal/d 21.2 mgd estimated new demands for
both towns
11Subbasin Stress Ratios 95-99 (USGS)
- Water Withdrawals
-
- Water Availability
- in August at the 25th percentile using 7Q10
- Stress Basin Ratios currently range from
approximately - 0.11 to 0.39
- (USGS 1995-1999)
0.39
0.12
0.22
0.11
0.32
12Subbasin Stress Ratios at Precautionary Buildout
4.06
8.55
0.78
Assumes equal distribution of future withdrawals
across all five subbasins. Aggressive Buildout
Stress Ratios 0.33 4.06
1.58
0.80
0.82
0.33
0.59
0.86
1.51
13Subbasin Stress Ratios at Aggressive Buildout
5.21
8.55
Assumes equal distribution of future withdrawals
across all five subbasins. Aggressive Buildout
Stress Ratios 0.39 5.21
1.58
0.98
1.19
0.82
0.39
0.59
1.02
1.51
14Key Findings Coventry and West Greenwich
- Current water supply is adequate for current
demand. - Future water demands will increase by 14.4 21.2
mgd. - Current water supply is inadequate for future
demands at buildout. - During peak summer months of 2004, KCWA used
11.68 of its allotted 21.95 mgd. - There is a potential surplus of 10 mgd that can
be allocated to future use. - CONE and Amgen will make up 17-25 of new demands
and are near-term developments. - Zoning matters.
15Key Recommendations Municipal Planning
- ? Both Coventry and West Greenwich should
consider rural zoning in far western portion of
town. - Coventry saves water by having mixed 2-, 3-, and
5-acre residential zoning. - ? Institute a graduated growth management plan by
a two-town regional approach. - ? Amend Subdivision Review Enabling Act to
require proof of water availability at Master
Plan stages.
It is possible to reduce new demands by growth
management, rural residential zoning changes,
amendments to require proof of water at Master
Plan, and cooperating in Artificial Recharge
Pilot Project.
16Key Recommendations Water Management
Wholesale (Scituate) 17.45 mgd
Wells 4.50 mgd
- ? Utilize existing sources before new sources as
per SGP 721 S-3. - Mishnock Well Expansion rehab of existing
sources conservation. - ? Reduce consumptive use.
- Artificial Recharge Pilot Project
- Landscape conservation ordinance
- ? Unnecessary at this time to develop new Big
River supply or CONE wells ? no OOBT.
Mishnock Wellfield 2.9 permitted not used 2005,
manganese contamination
Kent County 2001 Total Available 21.95 mgd
Kent County 2004 Uses 11.68 mgd
KCWA Potential surplus 2004 10.27 mgd
Big River Projected Wells 0-16 mgd
KCWA Mishnock Expansion 1.4 mgd
It is possible to meet all new demands (14-21
mgal/d) by expanding Mishnock to 4.3 mgal/d, by
operating all existing wells, and by using
conservation.
Conservation Demand Mgmt
Centre of New England Wells
17Special Thanks toCaroline Karp, advisor, Center
for Environmental Studies Brown UniversityDaniel
Varin, Chairman, Rhode Island Water Resources
BoardJennifer Paquet, Town Planner, Town of West
GreenwichHarold Ward, Center for Environmental
Studies, Brown UniversityKathy Crawley and RIWRB
StaffTimothy Brown, Kent County Water
AuthorityLynn CarlsonUEL Water Working
Group