Flow - Reservoirs
Skip Navigation Links

Flow includes a reservoir model based very closely on the ResSIM model developed by the USACE. The purpose of this model is to represent, to the greatest extent possible, ResSIM within the Envision framework.  It is built around two central concepts - defining individual reservoirs in the system, and defining control points, points in the stream network reporeseting points whose flow rates influence  reservoir operations.

document describing the technical details of the ResSIM model employed in Envision is provided here

Like other aspects of Flow, reservoirs are specified in the Flow Xml input file, as well as additional external reservoir files, defined within the <reservoirs> tag. Within this tag, individual reserrvoirs are defined with <reservoir> tags, one for each reservoir defined in the system, and individual control points are defined with <control_point> tags. Attributes for the <reservoir> and <control_point> tags are defined below.  In general, the Xml for specifying reservoirs uses the following general form:

 

Within {myflowmodel}.xml
<?xml version="1.0" encoding="UTF-8"?>

<flow_model>
    ...
    <reservoirs col="ResIDCol" >
      <reservoir name="Res1" ... />
        ...
      <reservoir name="ResN" ... />
        
      <controlPoint name="CP for Res1" ... />
        ...
      <controlPoint name="CP for ResN" ... />
    </reservoirs>
    ...
</flow_model>

Tags used to define reservoirs and control points for Flow are defined below. The tags include:


<reservoirs>

AttributeDescriptionDefault ValueRequiredExample Usage
col column in the Streams coverage containing the reservoir ID for each stream reach that contains a reservoirYes RES_ID
[top]

 

<reservoir>

AttributeDescriptionDefault ValueRequiredExample Usage
name Reservoir name Yes My Reservoir
id Unique Reservoir ID Yes any integer
path Path of reservoirs main directory, where reservoir input files are stored.
initVolume Initial volume, set to lower value of flood control pool, m3
area_vol_curve Filename of text file with area, volume and pool elevation relationships
av_dir Directory containing area volume curves
rule_curve Filename of text file with rule curve information
rc_dir Directory containing rule curves
buffer_zone Filename of text file containing the buffer zone curve values
composite_rc Filename of text file with release capacity information
re_dir Directory containing release capacity curves
rp_dir Directory containing rule priority file
rule_priorities Filename of text file with rule priority information, by zone (e.g. flood control, conservation, buffer)
cp_dir Directory containing text files with control point constraints (accessed by multiple reservoirs)
minOutflow Minimum outflow (cms)
maxVolume Maximum reservoir volume (m3)
td_elev Top of dam elevation (m)
inactive_elev Inactive elevation (m)
fc1_elev Flood control elev (m) – only if more than 1 flood control zone exists
fc2_elev Flood control elev (m) – only if more than 2 flood control zones exist
fc3_elev Flood control elev (m) – only if more than 3 flood control zones exist
maxPowerFlow Physical maximum flow that can be passed through the powerhouse
ro_rc Filename of text file containing capacity information for regulating outlets (typically dependent on pool elevation).
spillway_rc Filename of text file containing capacity information for spillway outlets (typically dependent on pool elevation).
tailwater_elev Elevation of tailwater (m). Used in hydropower calculations.
turbine efficiency Reported turbine efficiency (values taken directly from ResSIM). Used in hydropower calculations.
p_maintainence Probability of maintenanceename
ressim_output_f Filename of file containing flow output from ResSIM model (used for model comparison purposes)
ressim_output_r Filename of file containing rule output from ResSIM model (used for model comparison purposes)
[top]

<controlPoint>
AttributeDescriptionDefault ValueRequiredExample Usage
name Name of control point (names used directly from ResSIM)
Id Unique numerical ID
Dir Directory where the text file describing constraints at the control point is located
Control_point Name of the text file describing constraints
Location COMID of the reach within which the control point is located
Reservoirs A list of all the reservoir that this particular control point influences
[top]

Operating parameters for RESSIM-Lite are defined using a set of CSV files. The operating parameters are organized using four files:

  • Area Capacity Curves
  • Reservoir Rule Curve
  • Release Capacity Curve
  • Rule Priority Table

Rule Priority Table

The rule priority table contains a list of constraints, from lowest priority on top to highest priority on the bottom, for each operation zone within the reservoir. The zones are organized as follows:
Zone 0Top of Dam
Zone 1Flood Control
Zone 2Conservation Zone
Zone 3Buffer Zone
Zone 4Alternative Flood Control 1
Zone 5Alternative Flood Control 2

Below is an example rule priority file (CSV format): Min_Daily_MaxD_BiOp.csv Min_Foster_min_for_Buffer_Zone.csvPow_Max_FOS_power_release.csv     
01234
Max_Drafting.csvMin_Daily_MaxD_BiOp.csvcp_Max_bf_Jefferson_23780423.csvMaxD_Decreasing_Rate_of_Change.csv 
MaxD_FloodDcrsRate_Fostr.csvMaxI_Increasing_Rate_of_Change.csvcp_Max_bf_Waterloo_23785687.csvMaxI_Increasing_Rate_of_Change.csv 
MaxI_FloodIncrsRate_Fostr.csvMax_Winter_and_Con.csvcp_Max_bf_Salem_23791083.csvRelease_10000cfs.csv  
Pow_Max_FOS_power_release.csv Spill_Min_Fish_Weir.csv Min_Daily_MaxD_BiOp.csv Spill_Min_Fish_Weir.csv  
 Pow_Max_FOS_power_release.csvMaxI_IncrseRampingRate_Fostr.csv Pow_Max_FOS_power_release.csv 
  Min_ConservFlow_Fostr.csv  
  Max_Winter_and_Con.csv  
  Spill_Min_Fish_Weir.csv  
  Pow_Max_FOS_power_release.csv  

The zone number is in the first row, and the names of the text files corresponding to each constraint are located in a list below. Each column in the table above is stored as an array of objects called ResConstraints within an object called a ZoneInfo. A ZoneInfoArray for each reservoir stores the array of ZoneInfo objects (5 in the example above). Each ResConstraint is a text file with allowable reservoir release values given 1 or 2 variables. There are 8 types of constraints described in the table below:
Rule typeFile headerConstraint Type
MinimumMin_1
MaximumMax_2
Increasing RateMaxI_ 3
Decreasing RateMaxD_ 4
Control Pointcp_ 5
Power Plant rule (gate specific)Pow_ 6
Regulating Outlet rule (gate specific)RO_ 7
Spillway Rule (gate specific)Spill_ 8

Operating parameters for RESSIM-Lite are defined using a set of CSV files. The operating parameters are organized using four files:

  • Area Capacity Curves
  • Reservoir Rule Curve
  • Release Capacity Curve
  • Rule Priority Table

These files are defined below.

Rule Priority File

The Rule Priority File