NAMEModflowp - Parameter-estimation version of the modular modelABSTRACTThis program is a new version of the U.S. Geological Survey modular, three-dimensional, finite-difference, ground-water flow model (MODFLOW), which, with the new Parameter-Estimation Package, can be used to estimate parameters by nonlinear regression. The new version of MODFLOW is called MODFLOWP (pronounced MOD-FLOW-P) and functions nearly identically to MODFLOW when the Parameter- Estimation Package is not used. Parameters used to compute the following MODFLOW model inputs can be estimated: layer transmissivity, storage, coefficient of storage, hydraulic conductivity, and specific yield; vertical leakance; horizontal and vertical anisotropy; hydraulic conductance of the River, Streamflow- Routing, General-Head Boundary, and Drain Packages; areal recharge; maximum evapotranspiration; pumpage; and the hydraulic head at constant-head boundaries. Nearly any spatial variation in parameters can be defined by the user. Data used to estimate parameters can include existing independent estimates of parameter values, observed hydraulic heads or temporal changes in hydraulic heads, and observed gains and losses along head-dependent boundaries (such as streams). Model output includes statistics for analyzing the parameter estimates and the model; these statistics can be used to quantify the reliability of the resulting model, to suggest changes in model construction, and to compare results of models constructed in different ways.METHODParameters are estimated by minimizing a weighted least-squares objective function by the modified Gauss-Newton method or by a conjugate-direction method.HISTORYVersion 3.4 98/05/18 - (A) Integrated the Hydrauluc Flow Barrier Package so that barriers can be defined when estimating PID=T parameters, and so that parameters used to calculate the hydraulic characteristic of the barrier can be estimated. (B) PAR1AP: ADMX set. Not used presently in MODFLOWP, but used in UCODE and may be needed to test different GN convergence options for MODFLOWP. (C) SSEN1V: Removed GOTO 50 statement so that all flow observations are considered for each timestep. This allows multiple flow observations within a timestep. Version 3.3 (A) Correction to SSEN1M for convertible layers. (B) Added subroutine TSTAT, which produces the correct statistic for calculating 95-percent linear confidence intervals, given the degrees of freedom. TSTAT is called from SEN1OT. This addition eliminates one of two functions served by the preprocessing program BCINT. The confidence intervals on the parameter estimates printed by MODFLOWP now use the correct critical value. (C) Modified RESANP.F to create subroutine RESANP, which is called from the end of MODFLOWP.F. The files of data for the plots are generated by MODFLOWP instead of requiring that a separate program be executed (PROGRAMMING NOT COMPLETE). (D) Modified PAR1AP to correct floating point precision computations. (E) PAR1AP and MAIN: Moved printing to the screen of everything except the sum of squared, weighted residuals from MAIN to PAR1AP. The following additional information now is printed to the screen: DMX, JMAX, PID(JMAX). (F) SEN1OT and MAIN: Moved printing to the screen of the sum of squared, weighted residuals from MAIN ro SEN1OT. (G) PAR1OT: Included the standard error of regression in the printing. Wrote data for multiple prior to file for RESANP. Converted printing from log base e to log base 10. (H) SSEN1O: In the runs test, there is now a check for if the number of runs equals the expected number of runs. (I) SPCG1P: Calculated JMIN and changed WRITE statements using format 525. This corrects a situation that produced a negative indice when the solver converged in fewer than ITER1 iterations. Version 3.2 97/10/09 - Corrected problems with the implementation of the ADV Package in version 3.1 which caused erroneous regression results (added call to SADV1O to routine SSEN1O and corrected IF statement in SADV1L so that x-position sensitivities are calculated correctly). Clarified some print statements in routine PAR1OT. Added default file name (files96) for the NAME FILE. The use of variables KSTP and KPER discussed in Hill (1992, p.155) is now used only with IPAR=0, when sensitivity arrays are calculated. When IPAR=-1 or 1, KSTP and KPER are used as described for MODFLOW. This correction eliminates an incompatibility with MODPATH. Eliminate attempts to caclulate the Run's statistic and the correlation between ordered weighted residuals and normal order statistics (eq. 38 of text) when divide by errors would result. Version 3.1 97/07/24 - ADVective-transport observation (ADV1) Package added to distribution. This package is documented in Anderman and Hill (1997). Version 3.0 97/05/25 - Code updated to include MODFLOW-96 capabilities, including CHD1, GFD1, HFB1, IBS1, RES1, and TLK1 packages. Note, the MODFLOWP parameter estimation and sensitivity analysis capabilities are not compatible with these additional packages. MODFLOW-96 is documented in Harbaugh and McDonald (1996a and b). This version of MODFLOWP is compatible with data sets from all older versions of MODFLOW and MODFLOWP. Corrected calculation of sensitivities for PID=ANI. The error occurred in versions distributed from July 1994 to June 1997. PCG2 changed so final interaction information for four iterations are printed when MUTPCG=1. Corrected various initialization problems. Changed dimensioning of some arrays back to the original MODFLOW dimensioning to coordinate with MT3D and other postprocessing programs. Version 2.15 96/12/15 - In FLW1RP, apply INT in IF statement using QCLS In OBS.F, now use NRES when assigning values to the D array. In SEN1AL, reinstated IOUHDS and IOUFLWS in the call and print statements. In SSEN1P, KT=0 and KB=0 moved out of if sequences. This caused problems on Silicon Graphics machines. In YCINT, changed nobs to nh before the Do 36 loop. In SEN1FN, when writing format 565, the indices for ISTRM were changed to 4 and 5 from 1 and 2. This affects the printout of the information listed in the beginning of the output for PID=KST parameters, but does not affect calculated results. Some subroutines were restructured by Evan Anderman which make the inclusion of new observations more straightforward. Subroutines SSEN1F and SSEN1H were replaced by HED1RP and FLW1RP; parts of SEN1AL were replace by HED1AL, FLW1AL, and OBS1AL; parts of SSEN1O were replaced with SHED1O, SFLW1O, SPR11O, SPR21O and SPR310. The new subroutines are distributed in the file OBS.F. Added label to the composite scaled sensitivities. In SSEN1G, checks for exceeding NSM or NSN are now made as the data are read. Repeated information printed when some parameters are defined was eliminated (SSEN1G). Version 2.14 96/10/01 - Distribution includes a PostScript file of the updated input instructions. Directory name and default file names changed to be DOS compatible. Bug fixes; for example, corrected SSEN1U so that the counter for multilayer wells is updated correctly when wells are dry and for transient problems; correction in SEN1FN related to vertical leakance parameters distributed as log-transformed values; and changes in statements calculating weights for flows. Updates to utility program YCINT to accommodate full weight matrix for flows. When calculating Beale's measure, simulation NOW will continue even if the solver does not converge. Checks global budgets for excessive errors (>5%), which would invalidate the calculated Beale's measure. Version 2.10 96/04/23 - Modified MAIN to accommodate nonlinear confidence interval subroutines that are being developed and to accommodate computation of regression statistics when convergence is by the SOSC criterion (DATA SET 13). Change in SEN1RP so that Beale's measure will be calculated correctly when there are unestimated parameter values (as indicated by negative group numbers in DATA SET 9). Corrected indices specification for double precision array in SEN1AL that would only affect calculations with adjoint states. Initialized array IT1 in pcg2ap to correct printing of 1's to indicate the first internal pcg iterations of transient problems. Full weight matrices for flow observations added by Steen Christensen of the University of Aarhus, Denmark. In DATA SET 5, negative values of IUH and IUF now can be used to eliminate printing. In the line preceding DATA SET 2A, negative values of IUP can be used to eliminate printing. Corrections made in subroutine SSEN1H that allow correct representation of transient head observations in multilayer wells. Version 2.8 96/03/01 - Correction which applies when cells are rewet: Update array CVWD in SEN1FN. Correction which applies when any RCH parameter is not the last parameter and NLLI1>4 on line 3 of the Parameter-Estimation Package input file: change in SSEN1R. Correction which applies when laycon=3 and contributions to vertical leakance are calculated using layer thicknesses specified in the first multiplication arrays: Inclusion of laycon=3 in if statement in sen1fn. Broke up some if statements that were causing problems with some pc compilers. Corrected write statement so that when more than 99 head-dependent boundary cells are used to define a parameter they are written correctly. Added statements to main so that information is printed to unit * after the calculation of heads or sensitivities and at the end of each parameter-estimation iteration. On most systems, unit * is the screen. This printing can be eliminated by setting new variable IOSTAR to 1. Changes were made to the table of information from all parameter-estimation iterations, and changes were made so that MODFLOWP would perform correctly when the Parameter-Estimation Package was turned off. Version 2.2 95/09/14 - Added error messages to help users adapt to the new version. Added a file named VERSION to the distribution to make it easier for users to identify what version they had. Revised internally used revision numbers for each distributed file. Includes nine new capabilities, including use of convertible layers for steady-state systems. Output contains more explanations to guide users. Added damping factor to PCG2 package. Version 1.11 94/01/14 Version 93/11/01 - Corrected calculation of sensitivities for PID=ANIV. Version 92/09/01 - Dimension statements modified to achieve compatibility with the Lahey compiler. Version 92/03/01 - Original release.DATA REQUIREMENTSInput files from MODFLOW Packages modified for compatibility with MODFLOWP, and an input file for the Parameter-Estimation Package that defines the estimated parameters and the observations used in the regression.OUTPUT OPTIONSTabular summaries of descriptive statistics and data. Postprocessors (bealep, bcint, resanp, and ycint) are available in Hill (1994) and included in distribution.SYSTEM REQUIREMENTSMODFLOWP is written in Fortran 77 with the following extensions: use of variable names longer than 6 characters and greater than 19 continuation lines. Generally, the program is easily installed on most computer systems. The code has been used on UNIX-based computers and DOS-based 386 or greater computers having a math coprocessor and 4 mb of memory.DOCUMENTATIONHill, M.C., 1992, A computer program (MODFLOWP) for estimating parameters of a transient, three-dimensional, ground-water flow model using nonlinear regression: U.S. Geological Survey Open- File Report 91-484, 358 p. Hill, M.C., 1994, Five computer programs for testing weighted residuals and calculating linear confidence and prediction intervals on results from the ground-water parameter-estimation program MODFLOWP: U.S. Geological Survey Open-File Report 93-481, 81 p.RELATED DOCUMENTATIONHarbaugh, A.W., and McDonald, M.G., 1996a, User's documentation for MODFLOW-96, an update to the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 96-485, 56 p. Harbaugh, A.W., and McDonald, M.G., 1996b, Programmer's documentation for MODFLOW-96, an update to the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 96-486, 220 p. Harbaugh, A.W., 1990, A simple contouring program for gridded data: U.S. Geological Survey Open-File Report 90-144, 37 p. McDonald, M.G., and Harbaugh, A.W., 1988, A modular three- dimensional finite-difference ground-water flow model: U.S. Geological Survey Techniques of Water-Resources Investigations, book 6, chap. A1, 586 p. The ADVective-transport observation (ADV1) Package is documented in: Anderman, E.R., and Hill, M.C., 1997, ADVective-transport observation (ADV) Package, a computer program for adding advective-transport observations of steady-state flow fields to the three-dimensional ground-water flow parameter-estimation model MODFLOWP: U S. Geological Survey Open-File Report 97-14, 67 p. Version 2 of Preconditioned Conjugate Gradient Package is documented in: Hill, M.C., 1990, Preconditioned conjugate-gradient 2 (PCG2), a computer program for solving ground-water flow equations: U.S. Geological Survey Water-Resources Investigations Report 90-4048, 43 p. The Stream Package is documented in: Prudic, D.E., 1989, Documentation of a computer program to simulate stream-aquifer relations using a modular, finite-difference, ground-water flow model: U.S. Geological Survey Open-File Report 88-729, 113 p. The Interbed-Storage and Time-Variant Specified-Head Packages are documented in: Leake, S.A., and Prudic, D.E., 1988, Documentation of a computer program to simulate aquifer-system compaction using the modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 88-482, 80 p. The General Finite Difference Flow Package is documented in: Harbaugh, A.W., 1992, A generalized finite-difference formulation for the U.S. Geological Survey modular three-dimensional finite- difference ground-water flow model: U.S. Geological Survey Open- File Report 91-494, 60 p. The Version 2 of the Block-Centered Flow Package is documented in: McDonald, M.G., Harbaugh, A.W., Orr, B.R., and Ackerman, D.J., 1992, A method of converting no-flow cells to variable-head cells for the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 91-536, 99 p. The BCF3 Package is documented in three pieces. It builds on two previous versions of the Block-Centered Flow (BCF) Package. Documentation for the BCF1 Package describes the fundamental function of all BCF Packages. This documentation is contained in the basic model documentation (McDonald and Harbaugh, 1988). BCF2 documentation describes the addition of the capability to convert dry cells to wet: McDonald, M.G., Harbaugh, A.W., Orr, B.R., and Ackerman, D.J., 1992, A method of converting no-flow cells to variable-head cells for the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 91-536, 99 p. BCF3 documentation describes the addition of alternate interblock transmissivities. The BCF3 code includes the capabilities of BCF1 and BCF2: Goode, D.J., and Appel, C.E., 1992, Finite-difference interblock transmissivity for unconfined aquifers and for aquifers having smoothly varying transmissivity: U.S. Geological Survey Water- Resources Investigations Report 92-4124, 79 p. The HFB1 Package is documented in: Hsieh, P.A., and Freckleton, J.R., 1993, Documentation of a computer program to simulate horizontal-flow barriers using the U.S. Geological Survey modular three-dimensional finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 92-477, 32 p. The Transient-Leakage Package (TLK1) is documented in: Leake, S.A., Leahy, P.P., and Navoy, A.S., 1994, Documentation of a computer program to simulate transient leakage from confining units using the modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 94-59, 70 p. The DE45 Package is documented in: Harbaugh, A.W., 1995, Direct solution package based on alternating diagonal ordering for the U.S. Geological Survey modular finite- difference ground-water flow model: U.S. Geological Survey Open- File Report 95-288, 46 p. The RES1 Package is documented in: Fenske, J.P., Leake, S.A., and Prudic, D.E., 1996, Documentation of a computer program (RES1) to simulate leakage from reservoirs using the modular finite-difference ground-water flow model (MODFLOW): U.S. Geological Survey Open-File Report 96-364, 51 p.REFERENCESAnderman, E.R., Hill, M.C., and Poeter, E.P., 1994, Two-dimensional advective transport in nonlinear regression--sensitivities and uncertainty of plume-front observations: in Warner, J. and others, eds., 1994 Ground Water Conference, Fort Collins, Colo., Proceedings, p. 55-62. (Describes a useful technique for using inverse methods to evaluate how well you might expect available and anticipated data to estimate a defined set of parameters.) Anderman, E.R., Hill, M.C., Poeter, E.P., 1996, Two-dimensional advective transport in ground-water flow parameter estimation: Ground Water, v. 34, no. 6, p. 1001-1009. Anderman, E.R, Hill, M.C., and Poeter, E.P., 1996, Presentation and evaluation of a new multi-stage parameter-estimation method using advective-transport observations: in Calibration and Reliability in Groundwater modeling, Proceedings of the 1996 Model CARE Conference, Golden, Colo., September 1996, International Association of Hydrological Sciences Publication 237, p. 179-188. Barlebo, H.C., Hill, M.C., and Rosbjerg, Dan, 1996, Identification of groundwater parameters at Columbus, Mississippi, using three- dimensional inverse flow and transport model: in Calibration and Reliability in Groundwater modeling, Proceedings of the 1996 Model CARE Conference, Golden, Colo., September 1996, International Association of Hydrological Sciences Publication 237, p. 189-198. (This is not an application of MODFLOWP, but it does provide an example of using nonlinear regression in an interesting situation.) Cooley, R.L., and Naff, R.L., 1990, Regression modeling of ground- water flow: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. B4, 232 p. D'Agnese, F.A., Faunt, C.C., Hill, M.C., and Turner, A.K., 1996, Death Valley regional ground-water flow model calibration using optimal parameter estimation methods and geoscientific information systems: in Calibration and Reliability in Groundwater modeling, Proceedings of the 1996 Model CARE Conference, Golden, Colo., September 1996, International Association of Hydrological Sciences Publication 237, p. 41-52. Giacinto, J.F., 1994, An application of MODFLOWP to a Superfund case study: in Warner, J. and others, eds., 1994 Ground Water Conference, Fort Collins, Colo., Proceedings, p. 103-110. Hill, M.C., 1990, Preconditioned conjugate-gradient 2 (PCG2), a computer program for solving ground-water flow equations: U.S. Geological Survey Water-Resources Investigations Report 90-4048, 43 p. McDonald, M.G., Harbaugh, A.W., Orr, B.R., and Ackerman, D.J., 1991, A method of converting no-flow cells to variable-head cells for the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 91-536, 99 p. Poeter, E.P., and Hill, M.C., 1996, Unrealistic parameter values in inverse modeling, A problem of benefit for model calibration: in Calibration and Reliability in Groundwater modeling, Proceedings of the 1996 Model CARE Conference, Golden, Colo., September 1996, International Association of Hydrological Sciences Publication 237, p. 277-285. Poeter, E.P., and Hill, M.C., 1997, Inverse models, A necessary next step in groundwater modeling: Ground Water, v. 34, no. 2, p. 250-260. Poeter, E.P., and McKenna, S.A., 1994, Geostatistical simulation and inverse flow modeling to reduce uncertainty associated with flow and transport predictions: in Warner, J. and others, eds., 1994 Ground Water Conference, Fort Collins, Colo., Proceedings, p. 47-54. Starn, J.J., 1994, Field application of nonlinear regression to estimate the parameters of a two-dimensional ground-water flow model, Calvert City, Kentucky: in Warner, J. and others, eds., 1994 Ground Water Conference, Fort Collins, Colo., Proceedings, p. 575-582. Starn, J.J., Arihood, L.D., and Rose, M.F., 1995, Geohydrology and simulation of ground-water flow in the aquifer system near Calvert City, Kentucky: U.S. Geological Survey Water-Resources Investigations Report 94-4239, 52 p. Tiedeman, C., and Gorelick, S.M., 1993, Analysis of uncertainty in optimal groundwater contaminant capture design: Water Resources Research, v. 29, no. 7, p. 2139-2153. Yager, R.M, 1993, Simulated three-dimensional ground-water flow in the Lockport Group, a fractured dolomite aquifer near Niagara Falls, New York: U.S. Geological Survey Water-Resources Investigations Report 92-4189, 43 p. Yager, R.M., and Hill, M.C., 1991, Comparison of hypotheses used to construct simulations of transient three-dimensional ground-water flow by nonlinear regression, in EOS, 1992 Fall Meeting Abstract Supplement: American Geophysical Union, p. 210.TRAININGParameter Estimation for the Modular Ground-Water Flow Model (GW3089TC), USGS National Training Center, usually offered alternate years. Preliminary six-month correspondence course starts in August of even numbered years; one week of classes at the USGS National Training Center is usually the first week of the following March.CONTACTSOperation and Distribution: U.S. Geological Survey Hydrologic Analysis Software Support Program 437 National Center Reston, VA 20192 h2osoft@usgs.gov Official versions of U.S. Geological Survey water-resources analysis software are available for electronic retrieval via the World Wide Web (WWW) at: http://water.usgs.gov/software/ and via anonymous File Transfer Protocol (FTP) from: water.usgs.gov (path: /pub/software). The WWW page and anonymous FTP directory from which the MODFLOWP software can be retrieved are, respectively: http://water.usgs.gov/software/Modflowp.html --and-- /pub/software/ground_water/ModflowpSEE ALSOcontour(1) - A contouring program for gridded data moc(1) - Two-dimensional method-of-characteristics ground- water flow and transport model mmsp - Modular Model Statistical Processor modflow(1) - Modular three-dimensional finite-difference ground-water flow model modpath(1) - Particle-tracking postprocessor program for the modular three-dimensional finite-difference ground-water flow model sutra(1) - Saturated and (or) unsaturated, constant or variable-density fluid flow, and solute or energy transport (2-dimensional finite-element code)

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