DEQ-CFW_00020681

Session Law 2015-196
Report of the NC Department of Environmental Quality
Division of Water Resources
on the
Projected Water -Use Demands and the Availability of Ground Water and
Surface Water
in the
Cape Fear River Basin
DEQ-CFW-00020681

Introduction.................................................................................................... I
Purposeand Scope ..................................................................................................
I
Surface and Ground Water Systems ........................................................................
I
Description of Surface Water Study Area ................................................................
2
Cape Fear River Water Supply Evaluation ................................................................
2 Cape Fear -Neuse River Basin Hydrologic Model ..............................................
3
B. Everett Jordan Dam and Lake ..................................................................
6
Conclusions........................................................................................
15
Surface and Ground Water — Quantity — Downstream of Lock and Dam #1 ........................
16
SurfaceWater — Quality . .................................................................................. 19
FlowData ...........................................................................................
19
WaterQuality Data .................................................................................
20
Water Quality Assessment ........................................................................
21
Nutrient Criteria Development Plan ............................................................
32
GroundWater — Quantity . ................................................................................
33
Geology............................................................................................ 33
Description of the Aquifer System ..............................................................
34
Ground Water Availability .....................................................................
37
GroundWater Demand ...........................................................................
41
Adequacy of Demand to Meet Supply ....................................................... 44
Summary and Conclusions .....................................................................
45
DEQ-CFW-00020682

PotentialConflicts ..........................................................................................
53
How much can I withdraw? Instream and Offstream Uses .................................
53
Upstream vs. Downstream ..................................................................... 56
Inbasin vs. Out of basin ................................................................ ........
56
Recommendations......................................................................................... 58
Use of Existing Regulations ......................................................................
58
Use of Previous Planning Efforts ................................................................
60
Use of Basin Stakeholder Groups ...............................................................
63
Legislative Initiatives .............................................................................
63
AddressData Gaps ...........................................................................
65
ModelingChanges .............................................................................
65
Enhanced Review of Brunswick, New Hanover, and Pender Counties — Groundwater Focus
..............................................................................................................
65
References.................................................................................................... 68
Appendix I (this document includes appendices as well)
Appendix 2
14MT#Tff FIT= I
Table 1. Current and Requested Water supply Allocations
..............................................9
Table 2. Cape Fear River Water Supply Evaluation Model Scenarios
.......................................10
Table 3. Jordan Lake Minimum Values ................................................................. 12
DEQ-CFW-00020683

Table 4. Minimum Values Jordan Lake Flow Augmentation Pool and
Cape Fear River Flow at Lillington
......................................................................... 13
Table 5. Jordan Lake Water Supply Yield Analysis Results ......................................... 13
Table 6. Existing and Future Water Demands and Supplies in Black River RUC ................ 17
Table 7. Existing and Future Water Demands and Supplies in Northeast Cape Fear River HUC
.................................................................................................................. 18
Table 8. Demand vs. Supply - Cape Fear River Basin — via 8 Digit HUC
............................18
Table 9. Cape Fear River USGS Stream Flow Gage Stations Used for Water Quantity/Water
Quality Analysis for the Period Between 1/1/1983 and 8/7/2016
.......................................20
Table 10. 15A NCAC 02B .0200 NC Surface Water Quality Standards for Cape Fear River,
Class C and WS-1V Waters
........................................................................................ 21
Table 11. Cape Fear River Ambient Monitoring Station Percent Exceedance of a Water Quality
Standard and the Corresponding Mean or Median Concentrations for Dissolved Oxygen (DO)
and pH at the Three Different Flow Categories (Low, Mid and High -Flows)
..............................21
Table 12. Cape Fear River Ambient Monitoring Station Percent Exceedance of the Fecal
Coliform Bacteria Water Quality Standard and the and the Corresponding Mean and Geomean at
the Three Different Flow Categories (Low, Mid and High -Flows)
................................................24
Table 13. Cape Fear River Ambient Monitoring Station Percent Exceedance of a Water Quality
Standard and the Corresponding Mean Concentrations for Turbidity and Chlorophyll a (Chl a) at
the Three Different Flow Categories (Low, Mid and High -Flows)
....................................26
Table 14. Approximate Historical Flows Which Limit Algal Productivity Behind Lock and Dam
#1 and Lock and Dam #3 and the Percent of Time Below That Flow
..................................30
Table 15. Cape Fear River Ambient Monitoring Station Nutrient Mean/Average Concentration
at the Three Different Flow Categories (Low, Mid and High -Flows)
..................................... 11
DEQ-CFW-00020684

Table 16. Demand vs. Supply Predictions and Withdrawal Capacities via 8-Digit HUC
..........42
Table
17.
Ground
Water Supply and
Demand Summary (first
section)
...............................46
Table
17.
Ground
Water Supply and
Demand Summary (second
section)
...........................47
Table
17.
Ground
Water Supply and
Demand Summary (third
section)
..............................48
Table
17.
Ground
Water Supply
and Demand Summary
(notes)
.......................................49
Table
18.
Agricultural
Ground Water
Demand
..........................................................50
Table
18.
Agricultural Ground
Water Demand
(notes)
.................................................51
Table
19.
Daily
Average Ground
Water Withdrawals for
Counties
...................................51
Table
20.
Private Residential
Well Data for
Counties
...................................................52
Figure 1. Geographic Scope of Cape Fear - Neuse River Basin Hydrologic Model ................4
Figure 2. Cape Fear - Neuse River Basins Hydrologic Model Schematic ............................ 5
Figure 3. Jordan Lake Storage Diagram
.................................................................... 6
Figure 4. Duration of Jordan Lake Water Supply Storage ............................................. 11
Figure 5. Duration of Jordan Lake Flow Augmentation
Storage...................................... I I
Figure 6. Jordan Lake Reservoir Elevation Duration ..................................................
12
Figure 7. Flow Duration Lock & Dam #1 .............................................................. 15
DEQ-CFW-00020685

Figure 8. Cape Fear River Basin — 8-digit HUCs — Black River and Northeast Cape Fear River
HUCsHighlighted ..........................................................................................
16
Figure 9. Cape Fear RB Watershed Map
.................................................................. 19
Figure 10. Mean Dissolve Oxygen Concentration at each Station by Flow Category
...............22
Figure 11. Median pH Concentration at each Station by Flow Category
.............................23
Figure 12. Mean Fecal Coliform Bacteria Concentration at each Station by Flow Category
.......24
Figure 13. Geomean Fecal Coliform Bacteria Concentration at each Station by Flow Category
.25
Figure 14. Mean Turbidity Concentrations at each Station by Flow Category .....................
26
Figure 15. Instrearn Turbidity Concentrations at Low and High -Flow Categories at Lillington,
Station B6370000. (Red line indicates 50 NTU Turbidity Standard)
...................................27
Figure 16. Mean Chlorophyll a Concentration at each Station by Flow Category
...................28
Figure 17. Cape Fear River Chlorophyll a Instrearn Concentrations by Flow Category (Low,
Mid and High -Flows)
............................................................................................. 29
Figure 18. Chlorophyll a Concentrations at the Lower Flows for each Station
......................30
Figure 19. Mean Total Nitrogen Concentration at each Station by Flow Category
..................
31
Figure 20. Mean Total Phosphorus Concentration at each Station by Flow Category
..............32
Figure 21. Blue Green Algal Bloom (Microcystis aeruginosa) behind Lock and Dam #1 near
Kelly, NC on September 24, 2009
......................................................................... 32
DEQ-CFW-00020686

Figure 22. Hydrogeologic Cross Sections in the Cape Fear River Basin
.............................34
Figure 23. Ten Percent of Normal Distribution of Estimated Baseflow from Selected Cape Fear
River Basin Surface Water Gages
.......................................................................... 38
Figure 24. Process of calculating Gallons Per Day Per Square Mile for gaging station on Black
Rivernear Tomahawk .......................................................................................
40
Figure 25 - Average Daily Withdrawal Capacity for Each 8 Digit HUC in Cape Fear River Basin
.................................................................................................................. 42
DEQ-CFW-00020687