Model Requirements


The basic requirements for the Cape Fear River Basin Model have been refined over a period of months and years by personnel from the Division of Water Resources, other agencies such as the Corps of Engineers, and local stakeholder communities.  Included here is a summary of model requirements from the Request for Proposal.  See W9001   6/19/98W9001 #1   7/22/98, and W9001 #2  7/29/98 for details.

Model Capabilities

Model must be a mass-balance simulation tool
Simulate operation of Jordan Lake and other pertinent reservoirs,
Simulate flow conditions for major stream/ river segments of the river
Drought periods
Normal periods
Display a schematic basin map showing location of model nodes for reservoirs, stream segments, withdrawal and discharge points
Default model conditions must correspond to existing withdrawal and discharge conditions
Conditions must be allowed to vary with each time step of simulation
Allow user-defined withdrawal or discharge levels at any point in river
Simulate Corps' of Engineers existing operating poicies for Jordan Lake and keep separate accounts for water supply and water quality augmentation storage.
Default conditions correspond to existing operating policies
Allow user-defined reservoir operating policies that differ from existing policies.
Track low flow targets below Jordan Lake that can vary by month and according to the available water quality storage that remains in the lake.
Track individual water supply allocation accounts (amount withdrawn and storage remaining), the projected percentage of each allocation returned, the return location.
Begin simulations with user-defined reservoir storage volumes that are less than 100%.
Must characterize smaller impoundments such as Buckhorn Dam and proposed Randleman Dam.
Model must run on daily, weekly and monthly time steps,
Period of one year to maximum number of years of record.
Simulation period to be defined by simple menu screens.
Model must generate time-series of outputs at specified time step.
Must display system variables in an input/output layer to facilitate review of key model parameters and for sensitivity analyses.
Must be able to display history of river flow conditions at all selected model nodes during a simulation for all major river or stream segments.
For any modeled reservoir over the simulation period, the model should be able to display a history of:
Pool elevation,
Surface area,
Storage volume (by storage allocation account type),
Flow augmentation storage use,
Water balance information,
Annual summary tables for each modeled reservoir showing:
Maximum and minimum lake levels,
Water supply balances,
Flow augmentation balances,
Maximum tables must be for water year from 1 October to 30 September
Minimum tables must be for low flow water year from 1 April to 31 March.
Produce streamflow output data to be used in conjunction with a water quality model that is approved or supported by US EPA.  Stream profiles must be for a variety of flow scenarios, including 7Q10.
Produce flow output data at downstream boundary @ Lock & Dam No. 1 for use in hydrodynamic, water quality and estuarine circulation model for tidally-influenced portion of the river (if such a model is developed).
Model must support drought management planning and forecasting.  Specific drought evaluation techniques include:
Safe yield estimates for river withdrawals,
Return period estimates for user-defined Jordan Lake water supply storage yield values (default safe yield estimate is 100 mgd),
Track user-defined minimum instream flow targets at individual model nodes that vary by time step,
Evaluate water supply benefits from conservation scenarios.
Model must be flexible and documented to allow addition of new nodes for adding new withdrawals, discharges, or stream/flow evaluation points.  Nodes must not be hard coded into model.
Model must have enhanced graphical user interface and help screens.
Model must allow annually varying water consumption from agricultural used based on climatic conditions during the growing season.
Model must simulate flood operations by:
Looking ahead at least five days,
Route releases from node to node using a modified progressive average lag or similar technique,
Choose correct flood release operation based on projected flow rates at two different points downstream.
Model must be able to iteratively test various conservation measures to optimize conservation strategies.
Model to be developed in two phases.
Phase I - Input data collection and analysis, code modifications to MIKE BASIN to meet study requirements, particularly with respect to Lake Jordan operations, and simple drought management planning, a graphical user interface (GUI), model documentation and training.
Phase II - More elaborate flood routing capabilities, more sophisticated drought management planning, enhanced GUI, final model documentation and training.

Model Data Requirements

Inflow data
Actual historical streamflow, precipitation and evaporation records
Hydrologic period of at least 65 years where data are available,
Adjustment of gage flow data to produce naturalized, unimpaired flows for period of record,
Synthetic generation of inflows to extend short periods of record to entire 65-year period,
Model hydrologic record to include drought of 1930s.
Adjustment of gage flow data to include historical adjustments for regulation, consumptive uses, net evaporation, and transfers in order to generate naturalized flows.
Consumptive water use, discharges and transfers
Use DWR local water supply plan database and database of registered water withdrawals over 1.0 mgd.
DWQ's NPDES discharge database
Evaporation and Precipitation
Must be for same period of record as for the inflows
Reservoir Data and Operational Rules
Current operating policies for Jordan lake and other significant impoundments such as proposed Randleman Reservoir
Flow ratings of hydraulic outlets
Seasonal low flow targets downstream
Seasonal water withdrawals and return flows
Stage-storage-surface area ratings,
Discharge-stage relationships for flood control points downstream.
Agricultural Data
Identify significant irrigation users and rates of withdrawal
Estimate withdrawal rates for undocumented agricultural users based on data from known users.
Identify potential irrigation demand based on cropping patterns and actual weather conditions during the growing season.
Minimum Instream Flows
Identify stream nodes where minimum flow targets exist as the basis for Jordan Lake operations.
Track simulated stream flows at those nodes to evaluate the ability of various operating strategies to meet stipulated minimum instream flow targets.

Model Software

User-friendly, written for PC environment
Distributed on either standard floppy disks or by CD
Built for Windows 95/98 or Windows NT
Appropriate licensing arrangements
Run time for current conditions for 65-year period of record must be no more than 20 minutes on a Pentium II 300-mHz PC
Develop detailed documentation for users of the model.
Software must include training through workshops or classes,
Software must include technical support for up to five years.

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In Association With Our Funding Partners .. 

Cape Fear River Assembly

The Towns of Apex, Cary and Morrisville

Wake County.

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Last updated: May 11, 1999.