1. optimizing reservoir operations for water supply and ecological
objectives using flow modeling
Hernán A. M. Quinodoz, Ph.D. Delaware River Basin Commission Delaware Estuary Science Conference 2007

2. preview DRB basic facts flow management highlights
drought operating plans
basin reservoirs
DRBC daily flow model
flows versus ecological needs
use of the daily flow model
caveats

3. Delaware River Basin selected facts (1):
the longest undammed river east of the Mississippi – 330 miles
world-class trout fishery
wild and scenic river

4. … facts (2)
New York City, which lies outside the basin, gets roughly half its water from three reservoirs located on tributaries to the Delaware –
Cannonsville, Pepacton, and Neversink.
Water filtration is not necessary
Map: NYC DEP Web Site

5. Delaware River Basin (inter-state) flow management timeline
1931 – Supreme Court Decree
NJ sues NY and New York City
Equitable Apportionment of Water
1954 – Amended Supreme Court Decree
Case reopened by New York City
1961 – DRBC created, with authority to adjust the terms of the 1954 Supreme Court Decree, subject to unanimous consent of the five decree parties
1980’s – DRBC adopts drought management plans and Trenton flow target

6. 1954 Supreme Court Decree
NYC – 800 mgd combined (running average) diversion
Montague Target – 1750 cfs (1130 mgd)
NJ – 100 mgd diversion (D&R Canal)
No provisions for instream flow needs
No conditions on wise use of water

7. DRBC Drought Operating Plans
New York City Delaware Basin reservoirs drive the basin-wide operating plan.
Cannonsville
Pepacton
Neversink
Two Corps of Engineers reservoirs drive lower-basin operating plan
Beltzville
Blue Marsh
Montague
Trenton

9. Reservoirs for Interstate Flow Management in the Delaware River Basin
140 BG
96 BG
35 BG
15 BG (Emergency)
30 BG (Emergency)
11 BG (Emergency)
13 BG
16 BG
13 BG (Emergency)
6.5 BG
69 BG OF STORAGE FOR
FLOW AUGMENTATION MADE AVAILABLE THROUGH DRBC EMERGENCY ACTIONS
4.0 BG
Numbers indicate storage capacities
BG = billion gallons

10. Basin-wide Operating Plan Controls
NYC diversions
New Jersey diversions
Montague flow target
Trenton flow target
Salt line location
Conservation releases

11. salinity control – Upper Estuary
DRBC water-quality objective: maximum 30-day average Chloride concentration of 180 mg/L at R.M. 98
DRBC drought plan established Trenton flow target to provide for minimum freshwater inflows to the Estuary
Trenton flow target adjusts dynamically with the 7-day average location of the “salt line” (250 mg/L Chloride) in the estuary

12. DRBC daily flow model

13. DRBC daily flow model 1981 – Daily Flow Model developed by CDM as a
simulation model
2002 – OASIS developed by
HydroLogics, Inc., adding
optimization component to
meet conflicting demands
one-dimensional network of nodes at USGS gages (70+)
includes 12 major reservoirs
driven by historical unregulated hydrology (1928-present)

14. extension of daily flow model into the estuary
daily flow model does not include solute transport (e.g., chloride)
when salinity-related metrics are important, the daily flow model is coupled to a one-dimensional estuary hydrodynamics and chloride-transport model, which spans the estuary downstream of Trenton (currently available)
when resolving two- and three-dimensional hydrodynamics and transport is important, the daily flow model will have to be coupled to a higher-dimensional model (future)

15. incorporating ecological needs into models and analyses (1)
flow relationships are the simplest option
require a one-to-one relationship to a given model output variable (e.g., Trenton flow)
example: habitat vs. flow at nearest gage
can easily be built-in, avoiding need to run a post-processing (ecological) model
ecological metrics convert directly into flow model variable metrics

16. incorporating ecological needs into models and analyses (2)
sometimes more complex functions of flow are needed or unavoidable  example: habitat persistence, habitat spatial continuity
cannot easily be built-in, requiring development of a post-processing (ecological) model  example: USGS decision-support system (DSS) for eleven stream reaches in the Upper Delaware (habitat functions)
allows more complex evaluations, with user-controlled analysis (e.g., thresholds)

17. use of the daily flow model
supports DRBC decision making in a planning mode
modified periodically to incorporate changes in reservoir operation plans
utilized extensively to analyze alternative proposals
primary aid in designing new reservoir operation plans
available to interested stakeholders (several copies in use)
provides a common platform to test new ideas and learn about system behavior and performance
flexible tool, can adapt to changing needs
can be easily modified to incorporate new flow relationships and test new objectives

18. wrap up

19. Percent of drainage area controlled by reservoirs
caveats – reservoirs
Do reservoirs affect stream conditions downstream?
Yes, with significant effects directly downstream
Yes, with minor effects many miles downstream
Yes, with negligible effects hundreds of miles downstream
Percent of drainage area controlled by reservoirs
location
percent
Montague, NJ
42 %
Trenton, NJ
28 %
Chester, PA
20 %

20. caveats – general
here we focused only on the model as a tool, avoiding policy and management issues and constraints
technical solutions have to go through interstate negotiation process to eventually affect reservoir operations and management
scientific studies are needed to define ecological needs in the estuary and relate them to freshwater inflows (when appropriate)
extensive monitoring and modeling have to inform each other to maximize efficiency

21. science to support change: studies currently underway (UB)
Upper Delaware instream fish habitat assessment (USGS)
Upper Delaware instream temperature modeling (USGS)
Dwarf Wedgemussels in the Upper Delaware – Minimum flows required to sustain this federally endangered species
Dwarf Wedgemussel – Determination of Host Fish
Dwarf Wedgemussel – Habitat study on the Upper Delaware
Flow forecasting improvements for the Upper Delaware
Rate-of-Change in flow recommendations
Flow, temperature and biological monitoring in the Delaware River Tailwaters,
Fish Inventories of Upper and Middle Delaware River
Tri-State Watershed Management

22. summary DRB basic facts flow management highlights
drought operating plans
basin reservoirs
DRBC daily flow model
flows versus ecological needs
use of the daily flow model
caveats