HELP MODEL STEP-BY-STEP INSTRUCTIONS-
COMPILED BY TIM DAVIS FOR ES 470 LANDFILL PROJECT-
LAS CRUCES, NM
HELP MODEL
Computer Model Capabilities and Instructions for Use
Report Submitted to:
Dr. T. Sammis
New Mexico State University
Report Submitted by:
Tim Davis
ES 470-Environmental Impacts of Land Use
April 21, 1996
EXECUTIVE SUMMARY
This project entailed a thorough review of the Hydrologic
Evaluation of Landfill Performance (HELP) computer simulation
model capabilities and limitations. In addition, the model was
run for several different landfill scenarios to properly
characterize the step-by-step procedures to utilize this model.
The HELP model is used to simulate landfill conditions and
determine leachate generation through the different layers of a
preliminary design. The model uses user inputs for climate, soil
conditions, and design considerations to determine water
movement,vertical percolation, and leachate quantities. These
determinations are used to determine optimum design to ensure
minimal leachate production and comply with the State and Federal
regulatory requirements.
This project details the point-by-point set-up and use of the
HELP model. The project is divided into four different sections
as follows:
1. Initial Set-up and Computer Configuration Procedures,
2. Climatological Data Input Procedures,
3. Soil Conditions Input Procedures, and;
4. Design Criteria Data Input Procedures.
This project will enable a new user of the HELP model to operate
the system with minimal confusion, and ensure that procedures to
determine the required data are set forth. The information in
this document is intended to be used in tandem with the HELP
operations documents.
TABLE OF CONTENTS
SECTION FOR LINK
EXECUTIVE SUMMARY
INTRODUCTION TO THE HELP MODEL
COMPUTER SET-UP, MODEL INSTALLATION, AND CONFIGURATION
CLIMATOLOGICAL DATA INPUT PROCEDURES
SOIL AND LANDFILL DATA INPUT PROCEDURES
RUNNING THE HELP MODEL AND OBTAINING DATA
REFERENCES
INTRODUCTION TO THE HELP MODEL
The HELP model was developed by the U.S. Army Engineer Waterways
Experiment Station for the U.S. Environmental Protection Agency
to simulate water movement through landfill designs. The model
uses user supplied data inputs for climatological, soil
properties, and landfill design data to simulate the water
movement through the proposed design and calculate the leachate
generation at the drainage layers. In addition, the Model
calculates any leakage through the impermeable bottom liner
system to ensure the design captures and drains the leachate
produced. The model uses a solution technique that calculates
water budget analyses and accounts for surface storage, runoff,
infiltration, percolation, evapotranspiration, soil moisture
storage, and lateral drainage. These calculations are then used
in preliminary design proposals for landfill designers and permit
writers and reviewers such as State and Federal regulatory
agencies.
COMPUTER SET-UP, INSTALLATION, AND CONFIGURATION PROCEDURES
The HELP model must be configured on the computer to ensure
correct operation. The proper configuration ensures that the
model data files are not over-written, therefore data input can
be supplied once, then changed as required by the user. The
model is supplied on two floppy disks. The most efficient way to
use the model is to install the files on a computer hard drive,
then run the model with data files copied automatically to a
floppy disk. The model is run from the MS-DOS prompt. The
specific instructions to set-up the model are as follows:
1. Go to the DOS prompt and make a specific directory for
the copying of the HELP files. At the C: prompt, type
MDIR HELP to make the HELP directory. For these
instructions, the hard drive is assumed to be C: and
the floppy is A: drive.
2. Insert HELP disk 1 in the A: drive, then copy the files
to the HELP directory on the hard drive. At C:HELP>
type COPY a:*.* to install the files on the hard drive.
3. Repeat the procedure in Step 2 using HELP disk 2.
4. At C:HELP> type A: to change the drive to the A: drive.
5. Insert a new disk into the A: drive. This disk will be
the data files disk for the project. Copy the data
files from the C:HELP> directory onto the A: disk. At
the A: prompt, type COPY C:HELP/DATA4 to transfer the
data file to the new disk. Repeat this procedure for
DATA7, DATA10, DATA11, and DATA13.
6. The data files are now installed on the floppy disk.
When inputting information for a design, all the input
data will be copied to the data files on the floppy
disk. If more than one project is being analyzed, a
new floppy disk with copied data files is required. If
the same disk is used for a second design, the design
data inputs will be over-written. Separate disks for
separate projects will ensure data inputs for the
climatological, soil, and design information are not
over-written.
7. When inputting data or running the model, the commands
will be initiated from the A: prompt. This ensures the
data will be placed on the disk and not on the hard
drive. Model inputs can then be updated and editted as
required without completely re-inputting the data. The
commands for model execution are RUNHELPI for input and
RUNHELPO for running the model.
8. At the A: prompt, type C:HELP/RUNHELPI to begin the
data input procedures.
9. When all inputs are complete, type C:HELP/RUNHELPO at
the A: prompt to run the model and obtain the results.
CLIMATOLOGICAL DATA INPUT PROCEDURES
The climatological data can be entered into the model using three
different options; default precipitation data, manual
precipitation data, or synthetically generated precipitation
data. The default data is loaded in the model and includes
information from 102 different cities throughout the United
States. Each city has five years of precipitation data
available. The manual option allows the user to enter daily
site-specific data. The synthetic option generates up to 20
years of precipitation data using the city data and adjusting for
location by using user supplied mean monthly site-specific
precipitation data. The synthetic data option will generate
statistically similar data for the site location to the city
location closest to the facility. All the options generate daily
temperature and solar radiation data.
Using default data has limitations. The default precipitation
data included in the model is only five years for each city and
is available for the years 1974-1978. Unusually dry or wet
conditions may have occurred during these years. In addition,
the proposed location of the landfill may not be close to the
actual city data used. These limitations can be minimized by
using longer periods of data (up to 20 years), or editting the
default or generated data with site specific worst case scenario
precipitation data.
The input of default climatological data is completed as follows:
1. From the A: prompt, type C:HELP/RUNHELPI to initialize
the program and start the data input procedures.
2. At the SELECT INPUT OPERATION prompt, type 1 to enter,
edit or review climatological data. The program will
then show the menu of choices as shown below:
1 To use default rainfall data
2 To specify your own rainfall data or to edit
existing climatological data
3 To synthetically generate rainfall data
Select 1 to use default rainfall data. The
instructions for selecting option 2 or 3 will be
detailed later.
3. The program will then ask if you want a list of default
cities. Type YES or NO. A YES response will result in
a list of cities to choose from, a NO response will go
directly to the next question.
4. After the cities are listed, the program will ask for
the state of interest to be entered. Type the name of
the state in upper case letters; for example type
TEXAS.
5. Enter the name of the city of interest in upper case
letters, for example EL PASO. If the city is not
included in the 102 locations, the program will request
another selection.
6. The computer will respond ENTER THE LETTER OF THE DRIVE
WHERE THE DEFAULT PRECIPITATION DATA SHOULD BE READ.
Type the letter of the hard drive (for these
instructions, assumed c:), then press ENTER.
7. The program will respond LOAD THE CORRECT DEFAULT
PRECIPITATION DATA ON THE APPROPRIATE DRIVE THEN ENTER
YES. IF YOU MUST STOP EXECUTION TO LOAD THE DATA,
ENTER NO. The precipitation data is already loaded on
the hard drive, therefore type YES.
8. The program will respond ENTER THE MAXIMUM LEAF AREA
INDEX. The leaf index is based on the type of
vegetative cover used in the landfill design. The
index is defined as the dimensionless ratio of the leaf
area of actively transpiring vegetation to the nominal
surface area of the land on chich the vegetation is
growing. Typical values are shown by the program;
ranging from 0 for bare ground, to 5.0 for excellent
grass. Select an index and press ENTER. If the value
entered is greater than the default for chosen city,
the program will warn the user and suggest a typical
value for the location. The program will then respond
DO YOU WANT TO SELECT A DIFFERENT LEAF AREA INDEX?
Enter YES or NO, and select an index suitable to the
proposed design.
9. The program will then ask for the user to ENTER THE
EVAPORATIVE ZONE DEPTH IN INCHES and will show typical
values dependent on cover (bare ground to excellent
grass) for the chosen location of the design. Type in
an appropriate value, then press ENTER. The
evaporative zone depth is defined as the maximum depth
from which water may be removed by evapotranspiration.
10. The growing season for the default data will be
displayed and the user will be asked if modifications
are required. Type YES to change, NO to keep the
default growing season. If modifying the growing
season, the beginning and end date must be entered
using the Julian day.
11. Default data input for climatological conditions is now
complete and the program will return to the menu of
climatological input choices. Data can be reviewed
and/or editted by typing 1 at the SELECT INPUT
OPERATION to ENTER, EDIT OR REVIEW CLIMATOLOGICAL DATA,
then typing 2 to SPECIFY YOUR OWN RAINFALL DATA OR TO
EDIT EXISTING CLIMATOLOGICAL DATA.
To supply manually inputted climatological data, select 1 to
ENTER, EDIT, OR REVIEW CLIMATOLOGICAL DATA, then select 2 to
SPECIFIY YOUR OWN RAINFALL DATA OR TO EDIT EXISTING
CLIMATOLOGICIAL DATA. The following procedures delineate the
differences from the default procedure that are required when
inputting manual data:
1. After choosing the manual option, the program will list
the following menu:
1 To enter a new set of precipitation data
2 To add, delete, or replace years of existing
precipitation data
3 To check or edit daily values from existing
precipitation data
4 To enter/correct other climatological data
5 To exit
Choose 1 to manually enter the the site specific data.
To modify or check existing data or change the leaf
index or evaporative depth, or to compute daily
temperatures and solar radiation data, choose 2 through
4.
2. If precipitation data is not modified the program will
respond DO YOU WANT NEW DAILY TEMPERATURES AND SOLAR
RADIATION VALUES COMPUTED. Answer YES or NO. If
rainfall data is not changed, computations are based on
existing data; if the rainfall is modified the
temperatures will be computed automatically and the
message DAILY TEMPERATURES WILL BE COMPUTED SINCE
RAINFALL HAS BEEN CHANGED will be displayed.
3. Enter the manual rainfall data as requested from the
program. The previously delineated steps for the
default data input will be asked. These include
nearest city, leaf index, growing season, and
evaporative depth.
To synthetically generate rainfall data, the program requires
some different inputs than the default and manual input
parameters. The following steps for synthetic data are required:
1. Choose the generate synthetic rainfall option from the
precipitation choices menu.
2. Enter the same information for city and state nearest
to the facility location as previously performed for
the default and manual options.
3. After the city name is entered the program will respond
ENTER THE NUMBER OF YEARS OF DATA TO BE GENERATED.
Type the number of years wanted, then press ENTER.
4. The computer will respond DO YOU WISH TO IMPROVE THE
GENERATED RAINFALL DATA BY ENTERING THE NORMAL MEAN
MONTHLY RAINFALL FOR YOUR EXACT LOCATION? Enter YES or
NO.
5. If YES is entered, the program will respond ENTER THE
NORMAL MEAN MONTHLY RAINFALL IN INCHES FOR THE
SIMULATION PERIOD. ENTER THE VALUES FOR JANUARY
THROUGH JUNE. ENTER ALL SIX VALUES ON THE SAME LINE.
For example, type 2.3 4.5 4.8 6.6 5.6 7.0 leaving one
space between each number then press ENTER. If all six
values are not entered, the program assumes the number
is zero.
6. The program will respond ENTER THE VALUES OF NORMAL
MEAN MONTHLY RAINFALL VALUES IN INCHES. ENTER THE
VALUES FOR JULY THROUGH DECEMBER. Repeat the previous
procedure for this rainfall data. The program will
display the chosen values and ask if the user wants to
change them. Type YES if modification is required, NO
to continue.
7. Enter the maximum leaf area index as previously done
during default and manual data input.
8. Enter the evaporative depth as previously done.
9. Enter the growing season as previously done.
10. When the program asks if the user wants to correct the
location for the site latitude enter YES, then type in
the new latitude and press ENTER.
SOIL AND LANDFILL DATA INPUT PROCEDURES
The data inputs for the soil and landfill design include general
information about soil type and properties and the layer types
and design criteria for each layer. The program includes default
values for several different soil types and also includes
properties for waste layers and impervious liners. In addition,
user specified data inputs can be used, and the default or the
user specified data can be editted or modified at any time.
The procedures for data input using default soil properties are
as follows:
1. At the SELECT INPUT OPERATION command, type 2 then
press ENTER for ENTER, EDIT, OR REVIEW SOIL AND DESIGN
DATA.
2. The program will respond with the following menu:
1 To use default soil characteristics
2 To specify your own soil characteristics
3 To edit your existing soil and design data
3. Type 1 then press ENTER to use the default soil
characteristics.
4. The program will request a 3-line title. Type a three
line title with the name, location, and date on each
line. Press ENTER after each line is inputted. For
example:
CORRALITOS LANDFILL
CORRALITOS, NEW MEXICO
MARCH 14, 1996
5. The program will request DO YOU WANT THE PROGRAM TO
INITIALIZE THE SOIL WATER CONTENT FOR EACH LAYER? IF
YOU ANSWER NO, YOU WILL BE ASKED TO ENTER THE VALUE FOR
EACH LAYER. Type YES or NO, then press ENTER. Typing
YES instructs the program to run the first year of
simulation data, then use the soil water contents at
the end of the first year to initialize subsequent
years.
6. The program will then display the types of layers that
can be used in a design of the landfill and the rules
for placing the layers together. The layer types that
can be used are vertical percolation, lateral drainage,
barrier soil, and barrier soil with a liner.
7. The program will then respond ENTER THE NUMBER OF
LAYERS IN YOUR DESIGN. Up to 12 layers may be used and
4 barrier soil layers may be used. The layers are
numbered so layer 1 is at the top of the design and
subsequent layers below it. The program will respond
by displaying the top layer number and the bottom layer
number chosen for the design.
8. Information for each individual layer is then inputted.
The first request from the program is ENTER THE
THICKNESS OF SOIL LAYER 1 IN INCHES. Type the
thickness and press ENTER.
9. The program then responds ENTER THE LAYER TYPE FOR
LAYER 1. The layer type is chosen from a possible list
of four types as follows:
1 Vertical Percolation Layer
2 Lateral Drainage Layer
3 Barrier Soil Layer
4 Barrier Soil Layer With Flexible Membrane Liner
Choose the type of layer number and press ENTER. The
following figure gives a representation of design
criteria and how layers are generally designed.
CLICK HERE FOR FIGURE OF LAYERS
10. Several rules for the order of layers in the model must
be followed. These rules are as follows:
The top layer may not be a barrier soil liner.
Either a lateral drainage layer or a barrier soil liner
must follow a lateral drainage layer.
A barrer soil liner cannot be placed directly below
another barrier soil liner.
11. The program will respond ENTER THE SOIL TEXTURE OF
LAYER 1. The HELP model has default soil
characteristics based on USDA and USCS classifications.
The HELP model has numbered these layers from 1 to 20.
Included in these textures are liner soil
characteristics and municipal waste characteristics.
The textures are shown in Table 1.
CLICK HERE FOR DEFAULT SOIL CHARACTERISTICS TABLE
12. If the user specifies HELP texture numbers 19 or 20
(user specified characteristics) the computer will
respond ENTER THE WILTING POINT OF THE LAYER IN
VOL/VOL. The wilting point is defined as the lowest
soil waer content that can be achieved by plant
transpiration.
13. The program will then respond ENTER THE FIELD CAPACITY
OF THE LAYER IN VOL/VOL. The field capacity is defined
as the soil water content after a prolonged period of
gravity drainage. The field capacity must be greater
than the wilting point.
14. The questions for layer 1 will then be repeated for
subsequent layers. The design should include a barrier
soil liner under the bottom-most lateral drainage area.
If this is not in the design the model will ask the
user to specify one. If a barrier layer is not
specified, the lateral drainage from the bottom-most
drainage area will not be calculated.
15. After all the layers have been entered, the program
will respond SELECT THE TYPE OF VEGETATIVE COVER. The
program will supply options for cover from bare ground
to excellent grass. Choose one of the covers and press
ENTER.
16. The SCS curve runoff number will automatically be
calculated using the default vegetation and soil
texture of the top layer. The SCS number can be
entered by the user if the default value is not
accurate for site conditions. See the SCS Curve graph
for this purpose.
CLICK HERE FOR SCS CURVE DETERMINATION GRAPH
The program will respond DO YOU WANT TO ENTER A RUNOFF
CURVE NUMBER TO OVERRIDE THE DEFAULT VALUE. Type YES
or NO and press ENTER. If YES is chosen, type in a
number between 0 and 100. This number represents the %
runoff from the top layer.
17. The program will then respond IS THE LANDFILL OPEN OR
ACTIVE (UNCOVERED)? Type YES or NO, then press ENTER.
For manually entered soil and design conditions, the program will
respond with the same questions as for the default conditions.
However, the manual conditions data entry will include the
following additional requirements:
1. After the wilting point and field capacity are entered
as completed in the default section, the program will
respond, ENTER THE POROSITY OF SOIL LAYER 1 IN VOL/VOL.
The porosity is defined as the soil water content at
saturation.
For all soil texture entries, the porosity must be
greater than the field capacity which then must be
greater than the wilting point. Otherwise, the program
will request a new value.
2. The program will then request ENTER THE HYDRAULIC
CONDUCTIVITY OF SOIL LAYER 1 IN CM/SEC. The hydraulic
conductivity is defined as the rate at which water
drains vertically through a saturated soil with no
vertical pressure gradient. Enter the value and press
ENTER.
3. These questions will then be repeated for each layer in
the design.
4. When the data is being entered for a barrier soil
layer, the program will also ask for the leakage
fraction of the liner. The number can be between 0.01
to 0.00001 depending on the type of liner used. This
information can be determined from soil analyses (soil
liners) or from manufacturer's data for flexible
membranes. Enter the value and press ENTER.
5. For layers where the initial soil water content is not
initialized by the program, the program will respond
ENTER THE INITIAL SOIL WATER CONTENT FOR SOIL LAYER.
Enter the value and press ENTER.
For all entries of initial soil water content, the
value cannot exceed the porosity or be less than the
wilting point.
6. The program will then ask the same questions previously
delineated for SCS curve number, open or active
landfill status, then will ask whether the data would
like to be checked or corrected. If answer is YES, the
data will be displayed and can be changed by answering
the question for the line number of the data requiring
change, then typing in the change.
When typing a change for data, whether precipitation or
soil data, each data point from the entire line must be
typed in leaving a space between each number. If a
number is not entered, even if it is not being changed,
the program will assume it to be zero.
When all site soil and design data are entered and any data
checked and/or corrected, the program will switch routines and
request general site characterization questions. These questions
are as follows:
1. The program will respond ENTER THE TOTAL AREA OF THE
SURFACE IN SQUARE FEET. Enter the total area of the
landfill design and press ENTER.
2. Next, it will request ENTER THE SLOPE AT THE BASE OF
SOIL LAYER 1 IN PERCENT. Enter the slope of the top
layer and press ENTER.
3. The program will continue ENTER THE MAXIMUM DRAINAGE
DISTANCE HORIZONTALLY TO THE COLLECTOR, IN FEET. Enter
the distance between drains which are installed in the
lateral drainage area. If the design has more than one
lateral drainage area, the question will be repeated
for each layer.
4. If the initial soil water contents are either
calculated by the program (default data) or user
specified the program will respond, ENTER THE INITIAL
QUANTITY OF WAER ON THE SURFACE IN THE FORM OF ICE OR
SNOW. Enter the value, if applicable, and press ENTER.
5. If the user specified the landfill was an open site the
program will then request WHAT FRACTION OF THE DAILY
POTENTIAL RUNOFF IS ABLE TO DRAIN FROM THE SURFACE OF
THE OPEN LANDFILL. Enter a value and press ENTER.
6. The data for the design is now complete and the routine
will go back to the start and ask if you would like to
edit or change data or exit. Type the number that
corresponds to EXIT and press ENTER. This will make
the model exit the program and return to the DOS
prompt.
RUNNING THE HELP MODEL AND OBTAINING DATA
Running the model and obtaining output are accompolished by using
the RUNHELPO command. The model will run and provide either
detailed or summary output. Output showing daily values, monthly
totals, annual totals, average values, and peak daily values can
be obtained. In addition, a summary of the end of simulation
data can be generated. The procedures to run the model are as
follows:
1. At the A: prompt, type C:HELP/RUNHELPO and press ENTER.
The default drive is then the A: drive and the data
files loaded for the project are located on the A:
drive.
2. The program will respond SELECT OUTPUT CONTROL then
show a menu of choices as follows:
3 To run simulation and obtain detailed output
4 To run the simulation adn obtain only summary
output
5 To stop the program
3. The program will request LOAD THE CLIMATOLOGICAL, SOIL
AND DESIGN DATA ON THE DEFAULT DRIVE AND THEN ENTER
YES. The default data is on the default A: drive,
therefore type YES and press ENTER.
4. The program will respond HOW MANY YEARS OF OUPUT DO YOU
WANT, UP TO 20 YEARS MAY BE USED. Type the number of
years for simulation, then press ENTER.
5. The program will ask DO YOU WANT DAILY OUTPUT? Type
YES or NO and press ENTER.
6. Next, the program asks DO YOU WANT MONTHLY TOTALS?
Type YES or NO and press ENTER.
7. The program will respond ENTER THE DATA FILE NAME FOR
OUTPUT. Type a descriptive file name. For example,
CRUCES1.OUT, then press ENTER.
8. The program will respond, PLACE THE OUTPUT DATA
DISKETTE IN THE APPROPRIATE DRIVE AND ENTER YES. The
output data will be placed on the A: drive
automatically, therefore type YES and press ENTER.
9. The program will then begin the simulation and produce
an output file of the results. After completion of the
simulation, exit the program and return to the DOS
prompt. The output file can then be viewed using the
DOS editor command. At the DOS prompt, type EDIT then
the output file name and press ENTER.
For all subsequent simulations, if input data is
changed and the program runs, the data files will be
overwritten. If the user wants to run a different
simulation, a new disk with copied data files is
required.
All input data will be lost if a new simulation is run
without a separate disk. Use a separate disk for each
different run.
REFERENCES
Schroeder, P.R., Peyton, R.L., McEnroe, B.M., and Sjostrom,
J.W., Hydrogeologic Evaluation of Landfill Performance (HELP)
Model, Volume III: User's Guide for Version 2. Department of
the Army, Vicksburg, Mississippi. Working document prepared for
the U.S. Environmental Protection Agency. April,1992.
Schroeder, P.R., Peyton, R.L., McEnroe, B.M., and Sjostrom,
J.W., Hydrogeologic Evaluation of Landfill Performance (HELP)
Model, Volume IV: Documentation for Version 2. Department of
the Army, Vicksburg, Mississippi. Working document prepared for
the U.S. Environmental Protection Agency. April,1992.
New Mexico Environment Department, Solid Waste Bureau, Solid
Waste Management Regulations, EIB/SWMR-4, July 18, 1994.