ML050660005
| ML050660005 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 03/15/2002 |
| From: | Aladejobi T State of NC, Dept of Environment & Natural Resources |
| To: | Office of Nuclear Reactor Regulation |
| Hernandez S, NRR/DRIP/RLEP, 415-4049 | |
| References | |
| Download: ML050660005 (15) | |
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CAPE FEAR RIVER BASIN WATER SUPPLY PLAN SECOND DRAFT March 2002 Nt Division of Water Resources Division of Water Resources Department of Environment and Natural Resource ANW
Executive Summary The Cape Fear River Basin Water Supply Plan evaluates the long term water needs of water supply systems through 2050, and the effects of surface water withdrawals on the flows of the Cape Fear River. The plan looks at municipal water systems that use water from the Haw River, the Deep River or the Cape Fear River above'Lock & Dam #1, and municipal systems that discharge treated wastewater into the waters of these river basins. The plan includes information from 94 water systems in the following 19 counties: Rockingham, Guilford, Randolph, Alamance, Orange, Durham, Wake, Chatham, Montgomery, Moore, Lee, Harnett, Johnston, Cumberland, Hoke, Bladen, New Hanover, Brunswick and Columbus.
Our approach was to group water supply systems based on their existing interconnections, shared sources of supply, or interdependence, and then determine if there is enough water available within each mutually dependent group of systems to meet the projected needs of all systems within the group. Among the 94 water systems included in this analysis there are only four that are not connected to at least one other system for regular or emergency supply. For this analysis we evaluated each system independently, but within the context of the group of water systems that are mutually dependent on the same sources.
This analysis answers the question: is there enough water available in a particular area to meet the 2050 demands of the water supply systems in that area? The results of this analysis show that there appears to be enough water to meet the demands reflected in the 2050 estimates, if communities can develop the infrastructure to make use of it. However, the ability to develop efficient distribution systems and the ability to have additional water available by the time it is needed will depend on other factors such as funding and regional cooperation. Once again, the focus of the analysis was to determine if there is enough water available in the region to meet water supply needs over the next fifty years.
For our analysis of wastewater disposal, we again grouped water systems by their interconnections. The movement of wastewater does not necessarily follow the same pattern as the movement of drinking water, so the two means of grouping systems result in somewhat different groups.
While our analysis shows that there appears to be enough water available for communities in these basins to meet their projected demands, this may become a moot point if they cannot handle the wastewater they will generate. If the amounts of treated wastewater that a community or group can discharge to the waters of the state exceed NPDES limits and these limits cannot be increased, then they may have to develop alternative disposal systems. An effective demand management program could help control growth in water demand as populations increase, but as a community adds more people it will use more water and generate more wastewater. The actual amount of land will vary with soil and the amount of water to be applied. An inability to increase discharges could limit a community's ability to grow because of the difficulty of dealing with wastewater and/or the amount of land that would be required to deal with wastewater.
Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion
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The Regulation of Surface Waters Transfer Act and its associated administrative rule list specific criteria and standards for managing interbasin transfers of water. Analyzing and projecting future interbasin transfers, as defined by the statute and rule, requires information about the quantities and locations of water withdrawals, water discharges and consumptive uses.
We have not done such an analysis for this plan. Our analysis of interbasin water movement is limited to withdrawal and discharge quantities on an average day basis and water movement across major basin boundaries, only. This analysis differs from the Interbasin Transfer Law in that it does not consider the location of consumptive losses, is not on a maximum day basis, ignores the 2 mgd threshold, and does not consider subbasin boundaries. This analysis only describes the movement of water into and out of the major Cape Fear River Basin.
Based on these assumptions, in 1997 there was a net movement of 2.0 mgd from the Yadkin River Basin to the Cape Fear River Basin, 10.5 mgd from the Neuse River Basin to the Cape Fear River Basin, and 5.6 mgd from the Cape Fear River Basin to the Lumber River Basin; a total net water movement of 6.9 mgd into the Cape Fear River Basin on an average day basis.
By 2030, the net movement of water from the Yadkin to the Cape Fear could be 2.3 mgd, 4.3 mgd from the Neuse to the Cape Fear, and 10.6 mgd from the Cape Fear to the Lumber, a total net water movement of 4.0 mgd out of the Cape Fear River Basin.
We developed two modeling scenarios with the Cape Fear River Basin Hydrologic Model to evaluate long-term water supply needs in the basin. Scenario I evaluates the long-term water supply needs in the basin projected for 2050. Scenario 2 evaluates the basin water supply needs and recommended Jordan Lake water supply storage allocations for 2030. Lacking definitive information, we assumed that wastewater discharge permits would be adjusted to accommodate the amount of wastewater generated by the projected water demands for all water supply systems. We did not incorporate any drought management measures for Jordan Lake withdrawals or releases in these scenarios. We assumed that self-supplied industrial withdrawals and agricultural withdrawals would remain constant.
We had to make additional assumptions regarding individual water supply systems to develop the modeling scenarios. Our method of grouping systems based on water supply or xwastewater interconnections is appropriate for analyzing water supply needs, but for modeling we must assign specific water withdrawal and wastewater discharge locations for each water supply system. Each scenario is consistent with our analysis of water supply system groups.
These modeling scenarios allow us to analyze the predicted impacts of an entire set of projected basinwide water withdrawals and discharges. Other modeling scenarios could be developed with differing assumptions about specific water withdrawals and wastewater discharges, and still be consistent with our system groups analysis.
The results of modeling Scenario I indicate that, with a couple of exceptions, there is enough water to meet the 2050 projected needs for the water systems included in the analysis, without significant effects on the reliability of the Jordan Lake low-flow augmentation pool, the ability to meet the flow target at the Lillington stream gage, or downstream flows of the Cape Fear River. The exceptions are the towns of Robbins, Carthage and Vass. The present water supply sources of these towns may not be adequate to-reliably meet their projected demands.
Cane Fear River Basin Water Supplv Plan March 2002 Second Draft for Discussion
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Note that Jordan Lake water supply storage allocations do not impact the water supplies available to these communities in any way.
The results of modeling Scenario I and Scenario 2 indicate that the reliability of the low-flow augmentation pool will not change by 2030 and will decrease only slightly by 2050, compared with 1998. The 1998 model scenario results indicate that the flow augmentation pool has a 0.13 percent chance of being depleted on any given day, or is depleted during one year out of the 68 years modeled. Scenario 2 results indicate the same reliability for the year 2030.
Scenario I results indicate that the flow augmentation pool has a 0.37 percent chance of being depleted on any given day, or is depleted 4 years out of the 68 years modeled for the year 2050.'
This small decrease in reliability is a result of the large increases in projected demands for the water supply systems withdrawing water from the Deep River Basin and from the segment of the Cape Fear River between Jordan Dam and Lillington. The total projected increase in these withdrawals is 68 mgd by 2030 (an increase of 182 percent compared with 1998 withdrawals) and 113 mgd by 2050 (an increase of 302 percent compared with 1998 withdrawals). This means that multiplying the total withdrawals of all water supply systems affecting the flows at Lillington by four results in less than a one percent decrease in the daily reliability of the low-flow augmentation pool. Model scenario results also indicate that the slight decrease in reliability will not significantly affect the ability to meet the flow target at the Lillington stream gage. The flow profile at Lillington remains almost unchanged among the model scenarios.
The total projected increase in withdrawals upstream of Fayetteville is 114 mgd by 2030 (an increase of 93 percent compared with 1998 withdrawals) and 197 mgd by 2050 (an increase of 161 percent compared with 1998 withdrawals). Despite these large projected increases in upstream withdrawals, the flow profile at Fayetteville shows even less change among the model scenarios than the flow profile at Lillington. The Cape Fear River flows at Lock & Dam #1 are virtually unchanged among the model scenarios. Note that these modeled impacts on reliability do not incorporate any drought management for Jordan Lake or any water supply systems in the Basin. Drought management measures will improve the reliability of water supplies.
We expect this planning effort to continue as new information, such as the 2002 Local Water Supply Plans, becomes available. Information from this planning effort Vill be provided to the Division of Water Quality for use in the Cape Fear River Basinwide Water Quality Management Plan. Our next steps include:
- 1. developing additional modeling scenarios;
- 2. including additional model output analysis;
- 3. revising this draft document based on comments and corrections; and
- 4. incorporating drought management.
For additional information about the Cape Fear Hydrologic Model, model scenarios, or Jordan Lake allocations, please refer to our website at wwwnv.ncwater.org. Please direct any comments, corrections or concerns to Sydney Miller (919-715-3044 or sydney.millerencmail.net), or Don Rayno (919-715-3047 or don.raynoencmail.net).
'Note that during one of the four years that the low flow augmentation pool is depleted in Scenario 1, the pool is depleted for only one day.
Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion
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Table of Contents Executive Summary................
i Table of Contents................
iv Introduction......................................................................................................................................I Cape Fear River Basin...............
I Water Systems Included.
1 Information Sources.............
.3
.WaterSytem Service Populations.........................................4 County Populations......................................
5 Water Demand Projections...................
10 Water Supply System Groups......................
14 Available Water Supply......................
28 Water Demand v. Supply......................
31 Wastewater Discharge Projections............................
35 Wastewater Discharges v. Permit Limits..........................
37 Interbasin Water Movement..........................
44 Hydrologic Model..................
47 Model Scenarios..................
48 Model Inputs..................
48 Local Water Supply Systems..................
50 Model Scenario Results...............
62 Appendices Appendix A. Notes.......
A Appendix B. Population Projection Calculations.................................
B Appendix C. Water System Supplies.................................
C Appendix D. System Wastewater Discharges.................................
D Appendix E. Model Scenario I Inputs..................................
E Appendix F. Model Scenario 2 Inputs..............................
F Appendix G. Selected Model Scenario Analysis Tables......................................
G Appendix H. Assumptions.....................................
H Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion
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4 Introduction The Cape Fear River Basin Water Supply Plan evaluates the long term water needs of water supply systems through 2050, and the cumulative effects of surface water withdrawals on the flows of the Cape Fear River. We expect this planning effort to continue as new information, such as the 2002 Local Water Supply Plans, becomes available. Information from this planning' effort will be provided to the Division of Water Quality for use in the Cape Fear River Basinwide Water Quality Management Plan.
This document begins with an analysis of water supply systems by groups of systems and continues with a similar analysis focusing on wastewater. Following this general analysis we describe the more detailed analysis we used for hydrologic modeling and provide summaries of the model output analyses for the various modeling scenarios. Several appendices at the end include more detailed information than is provided in the general discussions.
Cape Fear River Basin The Cape Fear River Basin is located entirely within North Carolina. It is the largest river basin in the state, draining 9,149 square miles from the headwaters in the northern Piedmont to the mouth at Cape Fear, south of Wilmington. The Cape Fear River major basin is composed of the Haw River, Deep River, Cape Fear River, South River, Northeast Cape Fear River and the New River Basins. The Haw River and Deep River merge near Moncure to form the Cape Fear River which flows southeasterly to the Atlantic Ocean. The South River, Northeast Cape Fear River and New River Basins drain most of Sampson, Duplin, Pender and Onslow counties in the Coastal Plain. Most of the water systems in the Coastal Plain areas of the basin use ground water, except for water systems supplied by the Lower Cape Fear Water and Sewer Authority and the City of Wilmington, both of which have surface water intakes on the Cape Fear River. The rest of the water systems in the Cape Fear River Basin largel' rely upon surface water supplies.
The Haw River is impounded by the B. Everett Jordan Dam, just upstream of its confluence with the Deep River. Jordan Lake stores water to reduce downstream damage from flooding, to provide water supply and to supplement downstream flows. In addition, the lake provides recreational opportunities, including boating, swimming and fishing. -Water supply storage in the lake is controlled by the State of North Carolina and is allocated by the Environmental Management Commission (EMC).
WN'ater Systems Included The plan looks at municipal water systems that use water from the Haw River, the Deep River or the Cape Fear River above Lock & Dam #1, and municipal systems that discharge treated wastewater into the waters of these river basins. The plan includes information from 94 water systems in the following 19 counties: Rockingham, Guilford, Randolph, Alamance, Orange, Durham, Wake, Chatham, Montgomery, Moore, Lee, Harnett, Johnston, Cumberland, Hoke, Bladen, New Hanover, Brunswick and Columbus. We selected these water systems based Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion on information contained in the 1997 Local Water Supply Plans. We began with all water systems that are located in, or withdraw surface water or ground water from, the Haw, Deep and Cape Fear River Basins. Next, we included any water system that bought water from or sold water to our initial set of water systems. We also included any water system that discharges treated wastewater into any of the three basins under consideration. Figures on the following pages depict the Cape Fear River Basin and planning area.
Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion
Information Sources Local governments that provide water to the public are required to prepare a Local Water Supply Plan. These local plans provide vital information about water system characteristics and expected changes in demand and supply. We compiled most of the information for the Cape Fear River Basin Water Supply Plan from the Local Water Supply Plan database. We obtained information for some water systems from applications submitted during Round Three of Jordan Lake water supply storage allocations.
Local Water Supply Plans provided information on water system characteristics through the year 2020. DWR staff estimated population, water demand and wastewater discharges for those systems not applying for water from Jordan Lake, through the year 2050. Systems applying for an allocation of water from Jordan Lake provided estimates of water system characteristics through 2050 in their applications. Our analysis accepts the information provided in the Local Water Supply Plans and Round Three Jordan Lake Allocation Applications as given. DWR staff resolved any discrepancies in the information provided.
Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion
Water System Service Populations Many factors influence how and when a community grows: local land use patterns and controls, development of new roads, installation of water and sewer, and the availability ofjobs, to namejust a few. All affect the growth and distribution of population within communities. For the purposes of this analysis we assumed that local officials have a better perspective of how their communities will grow than we do. Therefore, for those water systems that did not submit applications for Round Three of Jordan Lake allocations, we based our estimations of population growth beyond 2020 on the pattern, of population growth provided by local water systems in their Local Water Supply*Plans.
Local Water Supply Plans are updated every five years with 1992 being the first year on which most plans were based. The 1992 LWSPs are based on actual water supply and demand conditions in calendar year 1992. The 1997 updated LWSPs were based on water supply and demand in 1997. Both the 1992 plans and the 1997 updates included estimates of service population for 2000, 2010 and 2020 in addition to the actual figures for the reporting years of 1992 and 1997. By combining information from the 1992 and 1997 local plans we were able to Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion estimate future population based on actual population figures for 1992 and 1997, and population estimates for 2000, 2010 and 2020.
Our population projections for 2030, 2040 and 2050 are linear projections of the population data presented by each system in their Local Water Supply Plan for 1992 to 2020, or taken directly from Jordan Lake applications. This method assumes that over the period from 2020 to 2050, population growth will continue in the same pattern as reflected in the period 1992 to 2020. This method seems reasonable given the limits of existing information. Our population projection calculations are provided in Appendix B.
County Populations We also examined the cumulative affect of these locally derived visions of growth by comparing our population projections with the county population estimates developed by the Department of Administration's Office of State Budget and Management (OSMB). The State Demographics unit analyzes census information and develops county population projections through the year 2020. We used the same method to extend the OSBM county population projections from 2020 to 2050 that we used to extend water system service population projections.
Water system population figures used in our analysis of water supply needs are presented in the following tables. The data are presented by county and include estimated water system service population, estimated county population, and the percentage of the estimated county population represented by each water system's estimated service population. Notes for all tables in this document are explained in Appendix A.
If we assume there will likely be some people in every county that do not receive water from one of the water systems included in our analysis, then the total percentages of water system service populations for each county should not exceed the total county population.
However, there is a fair amount of uncertainty associated with all of the population estimates used in this analysis. In some cases when the estimates developed for individual systems are summed for each county they exceed our population estimates for the entire county. Service area population projections are therefore likely to represent a maximum growth scenario for 2050.
Given the uncertainty in projecting populations through 2050, we only call the reader's attention to these discrepancies as a possible measure of that uncertainty. The following tables compare estimated water system service area populations and county population. Explanations of the notes listed in the tables can be found in Appendix A.
Rockingham County Ihos I WATER SYSTEM
[
20 I
20m0 1
2020 I
2030 1
2040 1
2050 l
REOSVILLE Sene A
e opun I
4
.2 15.400 1S.
16.0 71 16.604 71
_01C PoWt 1%
1%6 15%
15%
159 15%
IICUGiGHA CO Se Area H an I
61%
1I 1%4 88!
892 i
i of CcerStV ption e
1%
1 Y I %
I 1%
If Ccundy Povsa~
in S 1X281
% 668 100.414 104 87Sl 109 07i 113 265 Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion Brunswick County
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W.VAt nx...h AA A.A
-A
A M
A_
AAZA Zulu Z841 8uj4 UR7NSMWCK CO 5A Am. Popuialc 88, 97.74 117,471 35i 171 tSZ862
- d Cr*y P.pisto 61%
8%
At 66%
68%
NORTH BRUNSVw ICK WSP Q(LAD SD}M A
Serw Ames PopdAo.n u
S 7
8 0T.
- dO CamPOcdslP^ion S
5%
1 5%
8%
NAVASSA Soe" Aesa Popul0.^
6 3J 6
6 76 8
4 12
_ of C untv Poput~
0.7%
06%
06%
06%
06%
05%
CASWEUBEAH SwAc Acts Popuiion^
307 400 6o 41 6
17
- of Ccu^ty P0"sf 04%
04%
04%
04%
03%
03%
HOLDEN BEACH So.^e Amws Popucn. 1A6 2 L7U0 S3f d courty POo.
1%
2%
3%
3%
4%
4%
L.ONG BEACH WATER SevA".
Pcpiecn 6,41A 6,7P5 I0318 12.15 1X791
% Of Cow* Pop-A^7%
7%
6%
6%
n OCEAN ISLE BEACH SQvwe Aa Pop^ulo 68c 31 5 7 -----
T I.81 3 :07o Of
%cwtf 1%
1%
1%
1%
1%
1%
.H..iaSrmsc Area Popu.Alon
- T 315 I.
- 1.
-:7h
_of_
C Ax Popuiatx 2%
1%
1%
1%
D I
V A
SOUTHPORT Serxe Area Popuion 6,57 7
T,67 10,6z I
- d COLSOY PopulatIk, 1%
7%
7%
7%
7%
7%
bUhbSET IEAC SvicArea PoCputo T8h 3.32 34 8
,80!
4,43
_ d COOPO IS3 2%
2%
3%
3 I
3%
4 Id Zr;
=.-2:1 I V3 1A.1 10%
1.0%
09%
91%
Whater Demand Projections This analysis is based on estimated average daily water demand. They are an annual average daily water use for a water system and reflect an averaging of the high and low demands that occur throughout the year. For most systems there will be a certain number of months where actual average daily demand is below the annual average and other months when daily demand is well above annual average. Each water system has to consider its particular use pattern and determine the amount of water it needs to have available to meet peak demands.
We estimated demands for water differently, depending on whether or not a system had applied for a Jordan Lake water supply storage allocation during Round Three. Systems that applied for an allocation provided demand estimates through 2050 in their applications. We developed water demand estimates through 2050 for non-applicants.
Applicants for Round Three of Jordan Lake allocations provided estimates of water demand through 2050. Where possible, applicants developed separate estimates for residential, commercial, institutional and industrial demands for their system. These estimates are combined with estimates of the additional water needed to meet production and distribution needs to arrive at an estimate of overall raw water demand for a system's service population through 2050.
DWR developed estimates of average day water demands through 2050 for the other systems included in this analysis based on information in their 1997 Local Water Supply Plans.
Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion
For these systems we based demand estimates on 1997 per capita water use and DWR-generated population estimates for 2030, 2040, and 2050. The 1997 per capita water use rates are calculated by dividing total water use for a system in 1997 by 365, then by the system's 1997 service area population. We multiplied our service population estimates for 2000-2050 by the 1997 per capita water use rate for each system to develop estimates of average daily water demand. We did not estimate water demands separately for each use sector. Therefore, increases in water demands are solely related to increases in service population since per capita water use is held constant for each system at the 1997 rate. There were five systems in this analysis that did not submit a 1997 local plan. We used information from their 1992 plans to develop estimates of future water demands. Water use rates for each water system are provided in the tables on the following pages.
This approach to estimating water demands is useful for planning purposes, but has significant limitations. The assumption that per capita water use will stay the same for each system over the next fifty years is unlikely to be true. This method also assumes that per capita non-residential water use will remain constant for each system, based on the year 1997. While changes in commercial and institutional water use are usually closely related to changes in population, industrial water use is not necessarily directly related to population.
Cape Fear River Basin Water Supply Plan March 2002
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Second Draft for Discussion
Lower Cape Fear WSA Group 2000 2sr0 202s0 2030 2040 2050Tot WATER SYSTEM Noi BA DOmnd BA Demand BA 0 nd SA Demand SA Dermand SA Dt.nd Avallable SuppIy MGO Mmoo MGO MGO MGO MVG mO WILMW3TON 11.543 11.952 13.078 14.3Y6 15.841 16.096 3.300 NEW HANOVER CO AORPORT 10 0.021 0.024 0.029 0.032 0.036 0.040 0.000 WRIGHITSVILLE BEACH 1.005 1.111 1.117 1.221 1.297 1.372 1222 AmE VALLEY 0.1134 0.156 0.174 0.198 0.220 0.241 0.165 NEW HANOVER CO FLEMiNGTON 4
0.f 2
03 62 a293 0.302 0.308 03 15 0.412 fIGttRE EIGHT 0..N03 0.355 0.99 0.44 0 517 0.579 0.642 0.564 CAROtNABEACH 0.645 0.742 0.834 0.923 1.014 1.104 0.890 KtOE BEACH 0.357 0.414 0.480 0.588 0.677 0ol6 0.824 LOWER CAPE FEAR WSA 10 6.5 MM 1.e 11.6s0 11.650 11.6i 11.650 53300 IRiNSWICK CO 11tJ28 U.45t tT 022 20.432 23.509 2.580 0.0o0 NORTHsRUNSWCK WSA "LAND SO) 3.12 0.494 osits 0.847 0.759 0.858 03 0.000 NAVASoA 0.47 0.053 0.062 0.009 0.078 0M04 0.000 ASWELL BEACH 0.169 0220 0.275 0270 o02 0314 0C000 HLMOEN BEACH 0.41t 0.799 A.435 1.787 2z17s 2.599 0.000 LONG BEACH WATER 0.22 1.030 1293 1S75 1Ji42 2110 0.000 OCEAN ISLE BEACH 0.490 MM589 0.708 0.869 1.013 1.157 0.000 SHAlLOT7E 0.217 0228 0239 0264 0264 0203 0.oo0 SOUJTHPORT 0.860 0.800 0928 1.117 1.t22 t48 0.000 SINISET BEACH 0.864 0.628 0.67n 014 1.040 1.105 0.000 YAWON BEACH 0.187 0.155 0204 0.229 0.251 0273 0.000 9ONTEREY HEIGKTS 0.109 0.122 0.134 0.149 0.163 o0T.77 0300 K*URRAYVIJ.E 1.333 1t.87 1S17 2.243 2.549 2.555 2.915 WAtNiT HLLS 0oW9 0.092 0.103 0.117 0.130 0.143 0.14 RUNNMEADE 0.057 00
.0.074 0.084 0.094 0.103 0.144 PRINCE GEORGE 0.057 0.08 0.074 0.004 0.094 0.103 0.100 WESY 0.043 0.0o 0 0.058 0.063 0.070 0.07 0.792
,oA LAARAt4 AA" A oAM Aotts oMnoa wim Ao..
{
Z)GnroupTotal fr CaeFa RS
.L53 4 5>
4.032 6o.89 07.t1 1
14il 115.451 Riegelwood 201 20230 200 2094 1
TO WATER SYSTEM Notes 0.t SAD mAnd SA and SACemond A
&Ad5A nd l Av.8a8b Supply MO0 OO mO mm mm 4G0 MGO RIEGELWOOOSO 4
0643 734 0 611 0620 627 0
635 106 10 GtoupTotaforCas"FerRS!
0.63 0.734 l
.. 11 0.620 l
0.6271 l O.
106.100 Wastewater Discharge Projections Used water has to be dealt with in any water system. In some systems wastewater is collected and treated at a wastewater treatment plant or water reclamation facility. Other systems rely on individual customers to develop on-site disposal systems, such as a household septic system, to handle their own wastewater. There are very few communities where all residents receive drinking water from a community water system and return all wastewater to a municipal wastewater treatment plant. Communities with sewer systems typically have a percentage of residents who are not connected to the sewer and use on-site disposal systems. In addition, there are many uses to which drinking water is put that do not allow recovery, such as lawn watering, fire fighting, street cleaning and cooling. Therefore, not all water withdrawn from a source is returned to a water body where it is available to other users. Each time a quantity of water is removed from the local water resource pool some of it is not returned and the amount available to other users is reduced.
Our method of projecting wastewater discharges was similar to our method of projecting water demands. Applicants for an allocation from Jordan Lake supplied estimates of future wastewater discharges. Local Water Supply Plans provide information on location of and average amount of wastewater discharges as well as discharge permit limits. We calculated a ratio of water discharged to water withdrawn in 1997 and used this ratio to estimate the amounts of future discharges based on our demand projections. We also calculated the ratio of wastewater discharged outside of the Cape Fear River Basin to total projected wastewvater discharged for Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion Brunswick County and New Hanover County As noted above, many communities in these two counties use water from the Cape Fear River. The City of Wilmington and the Lower Cape Fear Water and Sewer Authority (LCFWSA) each have intakes in the river above Lock & Dam # 1; In 1997, Wilmington supplied finished water to its customers and the New Hanover County-Airport water system. Because of the amount of water Wilmington has available to its system from the Cape Fear River, we have assumed that in the future it will become a regional supplier of finished water to systems in New Hanover County that currently rely on ground water. The LCFWSA provides raw water to the Brunswick County water system\\nd to several in dustrial customers. Brunswick County provides' finished water tq Carolina ShoresCaswell Beach, Holden Beach, Long Beachworth Brunswick Sanitary District,'OceanIsle BeacRtShill6tte, Southport, Sunsef Beach anfd'Yaupon Beiac:mThe iS North Brunswick Sanitary District also provides water to the Iavassa water system. In addition to the water it receives from the LCFWSA the Brunswick County water system has wells that' can provide 3.4_Mgd of water. Southport and Yaupon Beach also have wells tha-t-su-ppywater to ii their system~s.
Because the intakes for Wilmington and the LCFWSA are located close to each other, we calculated the available supply for each intake as half the available supply at that location. Our analysis assumes that 53.3 mgd is available at each of these intakes, given the 825 cfs 7Q10 estimate provided by the latest USGS report. We considered all the systems that currently obtain water from Wilmington or LCFWSA and the other local government water systems in New Hanover and Brunswick counties as a regional group. The 27 systems included in this group have a combined, projected 2050 average daily demand of 73.4 mgd. They have 115.5 mgd of available supply when the supplies from existing wells are combined with the 106.6 mgd available at the intakes located on the Cape Fear River. Based on this analysis it appears these. ll [i systems have enough water available to meet future demands.
Most of the water systems in these two counties experience seasonal fluctuations in service population and water demand. The data in the Local Water Supply Plans are not sufficient to project future demands during the months of increased seasonal water use. Seasonal water needs are considered to some extent, however, because of the way per capita water use was calculated for estimating future demands. Average daily water use for each water system is determined by dividing the total amount of water used in 1997 by 365. Therefore, the average daily demand reflects the increased amount of water used to meet summer demands.
Model Scenario Results The results of modeling Scenario I indicate that, with a couple of exceptions, there is enough water to meet the 2050 projected needs for the water systems included in the analysis, without significant effects on the reliability of the Jordan Lake low-flow augmentation pool, the ability to meet the flow target at the Lillington stream gage, or downstream flows of the Cape Fear River. The exceptions are the towns of Robbins, Carthage and Vass. The present water supply sources of these towns may not be adequate to reliably meet their projected demands.
Cape Fear River Basin Water Supply Plan March 2002 Second Draft for Discussion F
( LOWERCAWEFEARWSA PWSID Noel lWATER SUPPLY SOURCE AVAILABLE SUPPLY
/-M6MD-__
SOURCE BASIN 0465-999 23 ICape Fear River l
53.300 02-3 I
Total
\\
53300 N'
NORTH BRUNSWICK WSA (LELAND SD)
FPWSID I Notes I WATER t SUPPLY SOURCE AVAILABLE SUPPLY MGD SOURCE BASIN 04-10-035 l3.12,19 1 from BRUNSWICK CO 0.455 l
Total 0.000 l
NAVASSA PWSIO Notes WATER SUPPLY SOURCE AVAILABLE SUPPLY SOURCE MGD BASIN 04-10-065 19 from NORTH BRUNSWICK WSA 0.133 02-3 l
Total 0.000 CASWELL BEACH PWSID Notes WATER SUPPLY SOURCE AVAILABLE SUPPLY SOURCE MGD BASIN 04-10-055 19 fromBRUNSWICKCO 0.260 02-3 Total 0.000 HOLDEN BEACH PWSID Notes WATER SUPPLY SOURCE AVAILABLE SUPPLY SOURCE MGD BASIN 04-104060 19 from BRUNSWICK CO 0.822 02-3 I
Total 0.000 Cape Fear River Basin Water Supply Plan March 2002
-C-
.Second Draft for Discussion