Version 1.0

CE-QUAL-W2 has been under continuous development since 1975. The original model was known as LARM (Laterally Averaged Reservoir Model) developed by Edinger and Buchak (1975). The first LARM application was on a reservoir with no branches. Subsequent modifications to allow for multiple branches and estuarine boundary conditions resulted in the code known as GLVHT (Generalized Longitudinal-Vertical Hydrodynamics and Transport Model). Addition of the water quality algorithms by the Water Quality Modeling Group at the US Army Engineer Waterways Experiment Station (WES) resulted in CE-QUAL-W2 Version 1.0 (Environmental and Hydraulic Laboratories, 1986).

Version 2.0

Version 2.0 was a result of major modifications to the code to improve the mathematical description of the prototype and increase computational accuracy and efficiency. These changes were summarized in the Cole and Buchak (1995) User Manual. Numerous new capabilities were included in Version 2.0, including:

An algorithm that calculates the maximum allowable timestep and adjusts the timestep to ensure hydrodynamic stability requirements are not violated (autostepping)
A selective withdrawal algorithm that calculates a withdrawal zone based on outflow, outlet geometry, and upstream density gradients
A higher-order transport scheme (QUICKEST) that reduces numerical diffusion (Leonard, 1979)
Time-weighted vertical advection and fully implicit vertical diffusion
Step function or linear interpolation of inputs
Improved ice-cover algorithm
Internal calculation of equilibrium temperatures and coefficients of surface heat exchange or a term-by-term accounting of surface heat exchange
Variable layer heights and segment lengths
Surface layer extending through multiple layers
Generalized time-varying data input subroutine with input data accepted at any frequency
Volume and mass balances to machine accuracy
Sediment/water heat exchange

Version 3.0

Version 3.0 is a result of additional improvements to the numerical solution scheme and water quality algorithms, as well as extending the utility of the model to provide state-of-the-art capabilities for modeling entire waterbasins in two-dimensions. The new capabilities included in Version 3 include:

An implicit solution for the effects of vertical eddy viscosity in the horizontal momentum equation
Addition of Leonard's ULTIMATE algorithm that eliminates over/undershoots in the numerical solution scheme
Inclusion of momentum transfer between branches
The ability to model multiple waterbodies in the same computational grid including multiple reservoirs, steeply sloping riverine sections between reservoirs, and estuaries
Additional vertical turbulence algorithms more appropriate for rivers
Additional reaeration algorithms more appropriate for rivers
Variable vertical grid spacing between waterbodies
Numerical algorithms for pipe, weir, and pump flow
Internal weir algorithm for submerged or skimmer weirs
Three algal groups
Arbitrary constituents defined by a decay rate, settling rate, and temperature rate multiplier
Nine inorganic suspended solids groups
Dissolved and particulate biogenic silica
Age of water
Derived constituents such as total DOC, organic nitrogen, organic phosphorus, etc. that are not state variables
A graphical pre/postprocessor
Converted to FORTRAN 90/95 with Dynamic Array Allocation eliminating the need to recompile the code for each application
User defined evaporation models including the Ryan-Harleman model

Version 3.1

Version 3.1 is a result of additional improvements to the water quality algorithms including:

User defined number of

generic constituents
inorganic suspended solids
CBOD groups
algal groups
epiphyton/periphyton groups

Computation of kinetic fluxes (sources/sinks) for ease in water quality calibration
Ability to animate any state variable, such as dissolved oxygen, or derived variable, such as total organic carbon, as well as terms in the solution of the momentum equation
Redesign of control file inputs for easier use and code for easier understanding
GUI preprocessor
Salt water correction for DO saturation
Dynamic light extinction inputs
Dynamic topographic and vegetative shading algorithm
Spatially varying wind sheltering coefficients
CBOD nutrient recycling
Kinetic flux algorithms

Version 3.2

Version 3.2 is a result of additional improvements to the model. These new capabilities include:

Internal code rewrite to reduce code size, simplify code maintenance, and improve model execution speed
New screen display during model run-time. The new screen display allows for controlling the processor usage, examining output variables, and stopping, starting and restarting a model run on the fly. This allows the model user to stop a code, then make changes in the control file or any input file, and then restart the model at the point that it was stopped
Addition of a new algorithm to estimate suspended solids resuspension as a result of wind-wave action
Reorganization of the graph.npt file to allow more output control formatting possibilities
New turbulent kinetic energy-turbulent dissipation turbulence closure model was added to the model
Model restart capabilities are now working again

Version 3.5

Version 3.5 is a result of significant enhancements to the model. These new capabilities include:

Addition of the macrophyte model of Berger and Wells (2008) with a user-defined number of species
Addition of a zooplankton model with a user-defined number of species based on an updated version of the CE-QUAL-R1 model (Environmental Laboratory, 1995)
Addition of a new focusing or settling velocity for sediments that accumulate in the first order sediment model. In earlier versions, sediment focusing occurred at the velocity given foe POM. In this version a user can specify that focusing velocity. This means that sediments can still migrate toward the bottom of the channel over time even after they have hit the sidewalls of the channel
User-defined time-variable input of P and N associated with organic matter inputs. In earlier versions, the P or N associated with organic matter was based on a static stoichiometric coefficient specified in the control file. Now, the user provides in the input files the dynamic P and N associated with organic matter inputs from tributaries or inflows. This is essentially allowing for variable stoichiometry in the input boundary conditions
Based on the above refinement, the organic matter fractions within the model now have variable stoichiometry for P and N. This preserves P and N mass balances. The stoichiometry given in the input files is merely the initial value of the C-N-P stoichiometry of POM and DOM compartments. Hence, organic P and organic N are tracked correctly in the code
The first order sediment model also tracks the C-N-P correctly and has a dynamic stoichiometry as it accumulates organic matter in the sediment. Prior versions of W2 had a user-defined value of fixed stoichiometry for the 1st order sediment model
CBOD groups now have a user-defined settling velocity. Hence, the user can define organic matter groups as particulate and dissolved based on specification of the settling velocity. As in prior versions, CBOD has associated stoichiometry and if there is settling, it will accumulate in the 1st order sediment compartment
A sediment burial rate was added to the 1st order sediment model
A Monod formulation was implemented for the inititation of anaerobic processes and reduction of aerobic processes. In earlier model versions there was a specified oxygen concentration that acted like a step function turning these processes on or off

Version 3.6

This version is file compatible with version 3.5. Hence no changes need to be made to any input files. Even though there are some new features in the input files, these are not required for users of V3.5 and can be kept blank. The primary change is allowing the code to run on multiple processors. The following changes have been made in the code from V3.5 to V3.6:

1. The code has been rewritten into smaller subroutines to allow better code compilation and optimization.

2. The code has been revised with the goal of improving the computational speed. This new compiled code using Intel Visual Fortran 10 should be faster on a single processor than the V3.5 code compiled on a PC with CVF 6.6.

3. The code now has OPENMP commands embedded to allow for limited parallelization of some of the routines. Current tests show that going from 1 processor to 2 can result in up to 20-40% speed improvement.

4. The TKE algorithm has been updated with new algorithms that match experimental tank data for kinetic energy and dissipation. This is based on a Master’s degree project by Sam Gould at Portland State University. A new user option is the TKE1 algorithm, in addition to the legacy algorithm TKE.

5. The roughness height of the water for correction of the vertical velocity wind profile is now a user-defined input, z0. Prior to this the model had hardwired the value of z0=0.003 m for wind speed correction at 2m (for evaporation where wind height at 2 m is typical) and z0=0.01 m for wind at 10 m (for shear stress calculations where wind height of 10 m is typical). For consistency, both conversions now use the same value of roughness height. If the user does not specify the value of z0 (for example if he/she leaves the spaces blank for z0 using a V3.5 control file), the code uses 0.001 m.

6. The Windows user interface no longer uses Array Viewer. The dialog box and PC executable no longer require installation of Array Viewer (which is now obsolete) nor do they need the Array Viewer DLL. The Dialog box has some minor improvements: model run directory displayed and a progress bar.

7. Fixed error with Algae/chlorophyll a ratio in user manual and fixed pre-processor. The earlier language in the user manual discussed an Algae/Chlorophyll a ratio but presented information that was the ratio of chlorophyll a/algae – this has been revised and fixed in User Manual and in preprocessor.

8. Spreadsheet output: in earlier versions put in an alphanumeric character as a space for the spreadsheet to preserve the formatting. This was changed to a default value of -99 to facilitate numeric data processing. Also, the “–Depth” output value was changed to just “Depth” since modern plotting programs can reverse an axis.

9. Preprocessor improvements. Added variable checks for new parameters, fixed bugs, new check for wsc.npt file (not checked in earlier versions).

10. For the generic constituent, added temperature dependence on 0th order decay and fixed errors in User Manual for units of zero order decay coefficient.

11. Added the kinetic flux rates to the TSR file output for easier analysis using a spreadsheet of the flux terms for specific locations in the modeled system.

12. Revised the computation of the drag coefficient for low wind speeds so that the model now agrees better with theory in this wind speed range.

13. The light extinction coefficient (in m-1) is now included as an output variable in the TSR opt file. Because the model internally computes the light extinction coefficient based on water, SS, POM, algae, zooplankton, and macrophytes, this is an important parameter understanding the internal light transmission predicted by the model. This variable replaces the equilibrium temperature as an output variable.

14. A new option for output is in the format required for TECPLOT. For TECPLOT animation there is only a flag in the CPL output line. This allows for easy model animation of the variables U, W, T, RHO, and all active constituents at the frequency specified by the CPL file as a function of distance and elevation.

15. A new variable for determining the fraction of NO3-N that is diffused into the sediments that becomes organic matter, or SED-N was introduced. 16. In V3.5 the model computed an average decay coefficient of the sediments based on what was deposited. The user now has the option to dynamically compute that decay rate or to have it fixed and controlled by the model user. A new variable was introduced called

16. DYNSEDK which is either ON/OFF to allow or not allow dynamic computation of the sediment decay rate.

17. Added Kinetic flux output that sums up fluxes for all cells of a waterbody at the output frequency specified in the kinetic flux output. The output filenames are called “kflux_jw#.opt” where # is the waterbody number. All active fluxes are summed for the waterbody. This is an important overall diagnostic tool to evaluate the important fluxes in the waterbody over time. Instantaneous fluxes are output in the TSR file for individual cells and a series of fluxes at given segments are shown in the Flux output file which is similar in format as the SNP file. This new file is easy to import into a spreadsheet for analysis.

18. The selective withdrawal algorithm computation was adjusted to more closely follow the Corps’ model code SELECT (based on personal communication with Gary Hauser, 2008). The variable DLRHOMAX is used to compute the relative velocity profile. In V3.5 and earlier, this variable was the maximum for the entire profile above and below the outlet, i.e., DLRHOMAX=MAX(DLRHOT, DLRHOB). In V3.6 and later, DLRHOT is used above the outlet and DLRHOB is used below the outlet.

Version 3.7

This version is not file compatible with version 3.6 because of the addition of several more state variables even though these are relatively minor. The release notes show where the control file differs from Version 3.6. Many of the new features to Version 3.7 are accessed through additional control files separate from the main control file, w2_con.npt. The following changes have been made in the code from V3.6 to V3.7:

1. The model has been improved to handle river flow regimes. These model enhancements for river systems include the following:

1. The initial water surface elevation of a river system based on the normal depth of the river is computed within the model. This allows the model to run more smoothly from the start and eliminates trying to guess an initial water surface elevation for a river system.

2. The model in earlier versions assumed that the initial velocity regime was ‘zero’. By computing an initial velocity regime based on the initial conditions of the flows, the river model then starts with a non-zero velocity. This allows the model to run more smoothly from the very beginning of the model simulation.

3. The model user can choose ‘Trapezoidal’ or ‘Rectangular’ model segments. This will allow for a smoother transition as water levels move up and down in a river channel. This should also allow for a larger maximum time step for stability in the river system.

4. The model user can now specify 2 slopes for a model branch. One slope is the slope of the elevation grid for which all elevations are tied together. The other slope is the hydraulic equivalent slope of a channel. In other words, if a model branch includes riffles and pools, the actual grid slope may not be the equivalent hydraulic slope.

2. There is a new bathymetry file input format in comma delimited format (csv) that is easily developed using ‘Excel’. This simplifies setting up the initial grid and debugging it.

3. Temperature and dissolved oxygen habitat volumes are now computed within the model for user-specified fish species.

4. There is a new automatic selection of a withdrawal port algorithm that will select the elevation of the withdrawal necessary to meet temperature targets including splitting flows between outlets to reach a target temperature.

5. Since each BOD group can have a different BOD-P, BOD-C and BOD-N stoichiometric equivalent, it was necessary to add to the model new state variables, BOD-P, BOD-N, and BOD-C that allowed for time variable inputs of BOD-P, BOD-C and BOD-N from a point or non-point source.

6. Environmental performance criteria were developed to evaluate time and volume averages over the system of state variables chosen for analysis. This is an easy method for looking at water quality differences between model runs.

7. The model now has a module for adding dissolved oxygen, such as hypolimnetic aeration, to specific locations based on a dynamic dissolved oxygen probe monitoring the dissolved oxygen levels.

8. The model has a dynamic pipe algorithm allowing a pipe to be turned ON or OFF over time, as if a gate was closed.

9. The model also has a dynamic pump algorithm that allows the model user to set dynamic parameters for the water level control over time. This is very useful in setting rule curves for operation of the reservoir water levels over time.

10. The maximum time step can now be set to interpolate its value over time rather than suddenly changing the maximum time step. This allows for a smoother change in the model time step.

11. The computation of the temperature at which ice freezes has been adjusted to account for salt water impacts. [Courtesy of Dr. Ray Walton]

12. New model output includes volume weighted averages of eutrophication water quality variables as a function of segment and for only surface conditions as specified by the model user. Other new output includes output of flows, concentrations, and temperatures from a segment for all individual withdrawals.

Version 3.71

This version is file compatible with version 3.7 but does add one new variable to the control file w2_con.npt.

1. New model input formats (free format) for many input files that were in fixed format. The new files allow for much easier model file development in Excel. These new files include the following files:

i. All concentration input files for inflows, tributaries, distributed tributaries and precipitation:

1. Cin files

2. Ctrib files

3. Cdtrib files

4. Cpre files

ii. Wind sheltering file

1. Wsc file

iii. Meteorological input file

1. Met file

iv. Vertical profile file for initial condition

1. Vpr file

v. Longitudinal-vertical profile initial condition

1. Lpr file

vi. Withdrawal flow file

1. Qwd file

vii. Structure outflow file

1. Qot file

2. New option for dynamic outlet structure elevation for each model structure. Hence, the center-line elevation of the structure can be variable over time. In the control file, there is an ON/OFF option after declaring the # of structures for each branch.

3. The release of a new post-processor from DSI, Inc. that uses the vector output in w2_con.npt to specify frequency of output for this post-processor.

Version 3.72

This version is file compatible with version 3.71 unless one uses the new USGS automatic port selection algorithm where the w2_selective.npt format is changed. This new version allows for using the algorithm of Rounds and Buccola (2015) with the automatic port selection for trying to meet downstream temperature targets from reservoirs.

Version 4.0

This version is file compatible with Version 3.72. All the new model options are contained in new control files other than the existing model files. The new model includes the following features:

1. Sediment diagenesis model of Prakash et al. (2011) and Berger and Wells (2014). This model includes bubble formation and rise in the water column, sediment consolidation, and sediment diagenesis. It includes the following new state variables:

a. Sediment and water column CH4

b. Sediment and water column H2S

c. Sediment and water column SO4

d. Sediment and water column Sulfide

e. Sediment and water column FeOOH(s)

f. Sediment and water column Fe+2

g. Sediment and water column MnO2(s)

h. Sediment and water column Mn+2

i. Sediment organic P, sediment PO4

j. Sediment organic N, sediment NO3, sediment NH4

k. Sediment Temperature

l. Sediment pH

m. Sediment alkalinity

n. Sediment Total inorganic C

o. Sediment organic C

p. Mature fine tailings (about 70% water and 30% fine clay – can take centuries to consolidate; from oil sands mining operation) – like another inorganic suspended solids group

q. Turbidity based on correlation with TSS

2. Non-conservative alkalinity from work of Sullivan et al. (2013)

3. Wind induced and boundary induced shear causing scour of organic matter from sediments and resulting oxygen demand

4. The new sediment model largely deprecates the older state variable Fe(total) since we now have different state variables for Fe and Mn

5. Ice formation and ice melting now affect the water body through loss or gain of water mass.

6. Periphyton and macrophyte variable areal density/concentration can be set for each model cell as well as setting a global initial concentration.

7. Output files tsr, qwo, two, cwo, structure, gate, pipe, pump, and spreadsheet files are now in comma delimited format rather than the older fixed format.

8. TSR file output now includes the limiting nutrient term for N, P, and light which is between 0 and 1

9. Photodegradation and gas transfer (volatilization) are now options for generic constituents

10. N2 gas is now an option for a generic constituent. If this is used, the model automatically computes %TDG using both N2 and O2 state variables

11. A floating skimmer weir can be used and is set up in the main control file section on internal weirs

12. A new output file format for longitudinal profiles of water level, temperature, flow rate and water quality are set up in the profile output section of the main control file

13. A new output file which gives a P and N mass balance for each waterbody including existing P/N in water column, in plants, and in sediments and fluxes in and out of the system including sediment release and P/N flux to the sediments

14. A new file format for head boundary conditions for head, temperature and concentration

Version 4.1

This version is file compatible with Version 4.0. All the new model options are contained in a new control file. The new model includes the following features:

1. Particle Tracking Algorithm based on revision and update to the Goodwin et al. (2001) algorithm. There is a new input file for activating the particle tracking algorithm, ‘particle.csv’, and documentation outlining how to use this algorithm is in the User’s Manual.

2. Branch active and inactive algorithm. In prior versions of the CE-QUAL-W2 model, if a branch lost water, the model would end. Now the model can activate or deactivate branches based on wetting and drying. Also, upstream inflows or tributaries are automatically added to the most downstream active segment of the in-active branch. This allows then filling and emptying a large reservoir with complex side branches with no further input of the model user.

3. Updates to the Sediment Diagenesis Model. These updates are focused on (1) increasing the speed of execution of the code, (2) improved input/output including adding sediment diagenesis fluxes of P and N to the massbal.csv file for analyzing big picture nutrient balance of a waterbody, and (3) Improved preprocessor checks of sediment diagenesis input parameters.

4. The value of Ax and Dx can now scale with the mean longitudinal velocity rather than being constants.

5. Canopy shade can be used in conjunction with the dynamic shade algorithm to estimate solar reduction when the channel has a vegetative canopy.

6. Assorted minor bug fixes and updates. [Thanks to Stewart Rounds, USGS, for suggesting several of these!]

7. Waterbalance console application for batch processing

8. Withdrawal output frequency now in days, hours, or sec for better precision and other I/O enhancements (volume weighted averages for the longitudinal profile file and SPR file).

9. The model now handles constrictions between segments, such as bridges and other obstructions.

10. Other changes still to be added to Version 4.1 include adding TDG and pH as input variables for in-flows/tributaries, vertical migration of algae, and further sediment diagenesis improvements.

Version 4.2

This version is file compatible with Version 3.72. All the new model options are contained in new control files other than in the main control file. The new model includes the following features:

1. Multiple waterbody cascade modeling using multiple processors. If the model is set-up for multiple independent waterbodies where flow moves from upstream to downstream, then the downstream models can run as they receive information from the upstream waterbody. This can save significant simulation time as multiple processors are used for each independent waterbody.

2. The User Manual was updated to a new format and organization with hundreds and hundreds of additions, updates, corrections.

3. The Corps of Engineers, SYSTDG, program for evaluating Total Dissolved Gas at spillways, was added to the release version of the model.

4. The restart feature with sediment diagenesis and Tecplot CPL output is now working. Prior to this version Restart did not work with sediment diagenesis and CPL output for Tecplot.

5. Updates were made to the sediment diagenesis code including input file name change, changes to output file names and formatting, and several bug fixes.

Version 4.2.1

This version is file compatible with Version 3.72 except for the new Excel version of the control file. The new model includes the following features:

1. Multiple waterbody cascade modeling using multiple processors has been updated using code developed by Stewart Rounds (USGS). This allows for a pause while waiting for upstream in-formation rather than a model restart allowing for more precise calculations.

2. A new control file, w2_con.csv, is now available for use in CE-QUAL-W2. This is derived from the Excel spreadsheet w2_con.xlsm which contains a macro to write the file into csv output format. This new file has many advantages compared to the fixed format file including no longer needing the graph.npt file. The User Manual, preprocessor and model executable have all been updated to allow for this input file. Also, a converter utility has been developed to transform legacy control files to the new version. This is described in the Model Utilities part of the User Manual.

3. The model examples and User Manual was updated with a new example problem from Long Lake, WA. This new example uses the new Excel form of the control file. Also, all example problems were developed with the Excel version of the control file.

4. The preprocessor now spawns a window showing the pre.err file in case there are errors detected in the preprocessor. Also, several new preprocessor checks were added.

5. Output file format has been improved for the w2.wrn and the W2errordump.opt files using suggestions from Stewart Rounds (tireless!).

6. The pump algorithm has a new enhancement allowing water to be pumped from the upstream to downstream based on downstream water level.

7. Tecplot output through the CPL output can now specify which branches to write out. A new input file, Tecplotbr.csv, is used to specify which model branches are output to the Tecplot file.

Version 4.2.2

This version is not file compatible with Version 3.72 since two new new variables were added to the control file. These are described in the User Manual Part 5 showing changes in the control file between versions. This code update adds a regression equation for CO2 global average concentration in ppm and allows the user to define an average CO2 gas concentration. This new calculation technique is described in the User Manual Part 2. The earlier code used a relationship that was from around 1960 (and had a minor coding error that had existed since Version 2)! Hence, the new addition for a time variable global CO2 atmospheric concentration.

Version 4.5

This version includes many new features and upgrades and is not file compatible with earlier versions because of many new variables in the control file. Differences between versions are shown in Part 5 of the User Manual. The new model includes the following features (the support of ERDC Environmental Laboratory and Portland District of U.S. Army Corps of Engineers provided many of these enhancements):

1. Atmospheric deposition of any state variable – model user provides mass loading to waterbodies. There is now no need to specify a flow, temperature, and concentration file since only a time series of mass per area per time is used as an input.

2. Ability to specify directly output of flow balance file, N and P mass balance file, water level file

3. New generic constituent source: sediment release

4. New state variables: water age, N2, dissolved total gas pressure, bacteria, CH4, Fe(II), FeOOH, Mn(II), MnO2, H2S. Many of these before were only operative using sediment diagenesis as generic constituents or were recommended generic constituents.

5. New derived variables: turbidity (correlated to TSS), Secchi disk (based on light extinction), un-ionized ammonia (based on temperature, pH, and total ammonia), and Total Dissolved Gas (TDG).

6. Ammonia volatilization is computed based on unionized ammonia volatilization rate and is a derived variable. pH must also be active as a derived variable.

7. Implementation of variable algal settling velocity including buoyancy effects from Overman (2019). This allows for predicting the variable velocity of cyanobacteria allowing for rise and fall of the cells during the day and night.

8. Zooplankton settling is a new zooplankton parameter.

9. Implementation of algal toxin production based on Garstecki (2021)

10. Ability to generate lake contours easily (elevation vs time for temperature and dissolved oxygen)

11. Ability to generate river contours easily (model segment or distance along river vs time) for temperature and dissolved oxygen)

12. The C groups dissolved organic C (DOC) and particulate organic C (POC) with both labile and refractory groups were added as an alternative to organic matter groups. The option is available to use either C or organic matter. This was done earlier by Zhong in an earlier version of W2.

13. Sediment diagenesis updates. Many updates were made allowing for multiple vertical layers, simplified calculation, and much faster computation than before. Now when sediment diagenesis is turned ON, both zero order and first order sediment models are turned OFF internally. Also, the sediment diagenesis input file format has been updated and integrated into the Excel master sheet. This work was performed by Dr. Zhang at PSU.

14. Removed internal minimum reaeration coefficient value and allowed model user to set a minimum value if required. For example, for waterbodies designated as ‘LAKE’ with zero wind, the model will now predict zero reaeration unless a minimum value is set. The reaeration coefficient for the surface layer is now an output in the Time Series file.

15. Updates to auto-port selection

16. SYSTDG input files updated to csv input format.

17. Updates to particle settling and P adsorption onto inorganic SS. A bug was fixed where dissolved oxygen controlled P adsorption to particles rather than just P adsorption to Fe.

18. All external control files are included in an Excel master sheet for ease of writing out as csv files.

19. % Dissolved oxygen less than 1 mg/l is part of habitat output.

20. Gates have enhanced functionality.

21. Meteorological data can be read in by segment groups or by waterbodies.

Version 5.0

1. A Hg model for the water column and for the sediment

2. A more advanced withdrawal algorithm for outflows from a dam

3. Ability to output data in HD5F format for external postprocessing

Planned Enhancements

The following model enhancements are planned for CE-QUAL-W2 along with their status:

#	Item	Description	Status
1	Fish	Fish Bioenergetics model	Tested and working in research code
2	Sediment transport		Simple model in research code
3	Smart particle tracking – Fish model		Tested and working in research code
4	Simultaneous water level solution	Currently, water surface is solved branch-by-branch. The new technique will involve solving all water surfaces for the system or waterbody simultaneously.	Tested and working in research code
5	W3	3D version of W2	Tested and working in research code
6	Hyporheic flow algorithm	Groundwater-surface water interaction	Tested and working in research code.
7	Sediment channel bottom heating algorithm	Dynamic heat transfer between channel bottom and stream	Tested and working in research code.