OSWER Directive 9481.00-GC 

CHAPTER II 

PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE WASTE CONSTITUENTS 

(40 CFR 264.94(b)(1)(i) and (2)(i)) 

The first step in any ACL demonstration is to identify the chemicals of concern. 

These "hazardous constituents" are chemicals listed in Appendix VIII of Part 261 of 

the regulations that have been detected in the ground water and may reasonably 

be expected to be related to the hazardous waste facility. The applicant must also 

account for the degradation products of all ACL constituents, especially if those 

products have significant toxicological properties. Once the hazardous constituents 

are identified, an ACL demonstration based on attenuation arguments must 

determine the physical and chemical characteristics of the constituents in order to 

effectively determine their transport through the environment and their ultimate 

fate. This chapter discusses the data that is needed to adequately characterize the 

physical and chemical properties of the hazardous constituents. 

The permit applicant should already know which hazardous constituents are 

present in the ground water at the facility by the time an ACL demonstration is 

being considered. The §270.14(c) permitting requirements specify that the permit 

applicant must determine the extent of ground-water contamination when a 

significant increase in a ground-water contaminant occurs at the compliance point. 

Additional ground-water sample collection and analysis is usually not necessary for 

ACL purposes. 

The hazardous constituents of concern during the permitting process can be 

any of the 375 contaminants listed in 40 CFR Part 261, Appendix VIII. The Agency 

does not require sampling for Appendix VIII substances that are unstable in ground 

water or for which no EPA-approved analytical method exists (U.S. EPA, 1984b). The 

permit applicant should be aware that the Agency has proposed changing 

Appendix VIII monitoring requirements for ground water (July 24, 1986; 51 FR 

26632). When this proposal is finalized (expected in June 1987), the Agency will use 

this list along with any site-specific additions to the list made by the Regional 

Administrator as the basis for detection and compliance monitoring programs. 

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Currently, an Appendix VIII analysis is required whenever any leakage from a 

facility's unit is detected by §§264.98 and 270.14(c)(4) monitoring. Assuring the 

absence of particular hazardous constituents emanating from a regulated unit is 

difficult to do simply by record-keeping. Wastes other than those that are currently 

received might have been placed in the unit in pre-record-keeping times. In 

addition, the potential exists for unpredicted reactions between the constituents 

and the formation of degradation products. 

The fulfillment of the §270.14(c) permitting requirements should result in the 

spatial characterization of each hazardous constituent found at the site. The permit 

applicant should submit, as part of the ACL demonstration, the data gathered to 

satisfy these requirements and present the information in terms of threedimensional representations of constituent concentrations. The three- dimensional 

representation of ground-water contamination may not necessitate threedimensional modeling of the contaminant plume. A two-dimensional model in the 

vertical and longitudinal planes may be sufficient in many cases, if the site 

hydrogeology is fairly homogeneous, and if sufficient monitoring data exists to 

describe the plume. See Chapter IV for further discussion of appropriate models. 

The permit applicant should also submit, as part of the ACL demonstration, 

information on the chemical and physical characteristics of the wastes in the 

regulated unit that was gathered pursuant to §264.13. This data will give the ACL 

reviewer a better understanding of what may be expected to show up in the ground 

water. Additional waste constituent analyses may not be needed for the ACL 

demonstration if the applicant has fulfilled the requirem~!nts of §264.13. 

Several physical and chemical characteristics of hazardous constituents are 

critical to the modeling of contaminant transport in ground water. Permit 

applicants should submit data on the following characteristics of the constituents 

for which ACLs based on fate and transport are requested: density, solubility, vapor 

pressure, viscosity, valence state, and octanol-water partitioning coefficient. For 

example, consider a facility that is leaking a hazardous constituent at a 

concentration level near or above the constituent's solubility level. In this case, 

there is a good possibility that a two-phase plume could result. One phase would be 

the dissolved constituent plume in the ground water, and the other would consist of 

relatively pure hazardous constituent. This latter phase c:ould either be floating on 

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OSWER Directive 9481.00-6C 

the water table or sinking to an aquitard, depending on its density. The two phases 

would probably move at different rates due to viscosity and density differences. 

Even when only one phase is present, the transport model results are 

dependent on the physical and chemical characteristics of the constituents; 

attenuation parameters for transport models depend on specific characteristics of 

the hazardous constituents. The permit applicant should submit in tabular form the 

density, solubility, vapor pressure, viscosity, and octanol-water partitioning 

coefficient values of the hazardous constituents. The ability for one constituent to 

mobilize other constituents should also be investigated. Appendix C contains an 

example of a summary sheet that can be used to list the important properties of the 

ACL constituents. 

An ACL demonstration that is based on attenuation should be supported by 

data on fate-related characteristics of the ACL constituents. If a permit applicant 

argues that the presence of an ACL constituent at the point of compliance is not 

likely to cause exposure because it is not persistent in the ground water, then 

special fate and stability related characteristics of the constituent should be 

discussed in the ACL demonstration. 

The stability of waste constituents in the subsurface environment can be 

affected by chemical, biological, and physical processes. Important chemically 

mediated subsurface processes may involve oxidation, reduction, and hydrolysis. 

Important biologically mediated processes include biodegradation and 

biotransformation reactions. The subsurface physically mediated processes can 

involve ion exchange, precipitation, and complexation reactions. If the ACL 

demonstration is based on any of these processes, then the results of site-specific 

tests should be submitted. Most of the degradation processes depend on the 

properties of contaminants as well as environmental factors such as microbial 

populations, solid surfaces, and dissolved constituents present in the ground water. 

Because the relevant environmental factors are unevenly distributed in nature, 

degradation and reaction rates are not constant in ground-water environments and 

must be assessed on a site-specific basis. Therefore, the use of general information 

gathered from the literature will be of limited value when assessing the stability of 

waste constituents. 

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OSWER Directive 9481.00-6C 

Degradation properties of the ACL constituents are also important in 

determining the effects of the constituents. Since deqradation products can be 

more hazardous than the parent compound, all known and likely degradation 

products should be discussed when describing the characteristics of the waste 

constituents. 

Grouping ground-water contaminants according to stability characteristics 

may be possible. If site-specific tests support the grouping of constituents, then the 

fate and mobility of each constituent within a group can be based on the stability 

characteristics of the most mobile and most persistent compounds m the group. This 

would result in the fate and mobility coefficients for each constituent being set at 

the coefficient values for the most mobile and most stable compounds in the group. 

Before grouping the constituents, the applicant should investigate possible 

degradation products associated with the constituents of concern. The ability of 

one contaminant to facilitate or hinder the movement of another contaminant (cosolvent effects) should also be accounted for when possible. Although it is difficult 

to decide which groupings of constituents are appropriate, grouping can reduce the 

amount of predictive modeling necessary for quantifying environmental 

concentrations and exposure pathways (see U.S. EPA 1986c). 

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OSWER Directive 9481.00-6C 

CHAPTER Ill 

HYDROGEOLOGIC CHARACTERISTICS 

(40 CFR 264.94(b)(1)(ii) and (2)(ii)) 

A general description of the hydrogeological characteristics of the facility is 

needed in all ACL demonstrations. A more detailed assessment of ground-water 

movement near a facility is essential to a demonstration based on attenuation. The 

main route of exposure to ground-water contaminants usually involves the 

movement of the hazardous constituents through the soil to the ground water and 

on to an existing or potential point of use. This chapter describes the information 

needed to adequately determine the hydrogeologic properties required for 

characterizing ground-water movement at a site. 

During the general RCRA permitting process, the permit applicant is required 

under §270.14(c) to identify the uppermost aquifer. The uppermost aquifer is 

defined under §260.10 as the geologic formation nearest the natural ground 

surface that is an aquifer as well as lower aquifers that are hydraulically 

interconnected with this aquifer within the facility's property boundary. Saturated 

zones above the uppermost aquifer are also of interest as contaminant migration 

pathways. Therefore, for an ACL demonstration based on attenuation, information 

on the geologic and hydrologic properties of each of the individual strata beneath a 

facility, that are likely to influence ground-water contaminant migration, should be 

submitted. This data is needed to adequately characterize ground-water transport 

mechanisms. Much of the data should already be available to the permit applicant 

if the Section 270.14(c) requirements have been fulfilled. 

The important geologic attributes of a facility include: 

1. Soil and rock characteristics, 

2. Geologic structure, and 

3. Geomorphology and topography. 

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OSWER Dorective 9481.00-GC 

When describing the soil characteristics of a facility, the permit applicant 

should use the Unified Soil Classification System or the U.S. Department of 

Agriculture's soil classification system. Each soil type beneath the site and within 

the areal extent of the ground-water contaminant plume should be investigated. 

The permit applicant should submit data describing the thickness, areal extent, and 

hydraulic properties of each soil type. The soil information should be submitted in 

both tabular and graphic form. The areal extent of soil types should be presented 

on a map with a scale no greater than one inch:200 feet. The applicant should 

submit copies of drilling and boring logs from monitoring and water wells that have 

been installed. 

If the applicant uses soil or other matrix attenuation mechanisms to justify the 

ACL, the additional data and calculations used to define the attenuative properties 

should be submitted. The following attenuation mechanisms may be relevant to an 

ACL demonstration: 

1. Dispersion, including hydrodynamic dispersion; 

2. Retardation, including all sorptive properties; and 

3. Degradation, including mechanisms of biodegradation, oxidation, 

reduction, and hydrolysis. 

The permit applicant should submit data describing the organic and mineral 

content, the cation and anion exchange capacity, and the grain size of each soil type 

in the area of contamination. Aquifer matrix characteristics that affect the stability 

of the ACL constituents (see Chapter II) should also be described if they are used to 

support attenuation claims. The results of tests to substantiate any attenuation 

claims should be submitted by the applicant. Likewise, sampling and laboratory 

procedures used to determine the attenuation propertiE!S should be presented and 

results tabulated. Brady (1974) and Freeze and Cherry (1979) provide in-depth 

discussions of these specific soil characteristics, and the permit applicant and 

reviewer should consult these references for assistance. 

The permitting authority and the applicant should keep in mind the outcome 

of the different types of attenuation. Although matrix effects (binding) and 

dispersion act to lower the concentration of the contaminants at the point of 

exposure, they do not directly reduce their total mass. Constituents that attach to 

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OSWER Directive 9481.00-GC 

the matrix may become mobilized at a later time. However, degradation 

mechanisms act to eliminate the contaminants themselves. This form of 

attenuation is permanent and, assuming the products are harmless, can be a final 

solution to eliminating the contamination. 

If the ACL demonstration is attenuation-based, the permit applicant should 

submit a set of maps that adequately depict the subsurface stratigraphy. The nearsurface stratigraphic units in the zone of saturation that affect or are likely to affect 

ground-water contaminant migration should be described. The areal and vertical 

extent of the hydrogeologic units can be presented in several ways. For complex 

settings, the most desirable presentation is a series of structural contour maps for 

the top or bottom of each unit. Vertical sections and isopach maps can also be used 

since they are generally more graphic and are useful as supplements to the 

structural contour maps. Because the construction of any of these diagrams involves 

interpolation and extrapolation of data, the diagrams should show the location of 

control points and the corresponding value at each control point. The site maps 

should include the depth, thickness, and areal extent of each stratigraphic unit. The 

maps should also adequately depict all stratigraphic zones and lenses within the 

near-surface zone of saturation. The site-specific stratigraphic maps should be 

detailed and have a scale no greater than one inch:200 feet. The applicant should 

also submit regional stratigraphy maps in order to show unique regional 

characteristics and their relationships to the site and to justify claims concerning the 

ultimate fate of a contaminant plume. A table that summarizes the subsurface 

geologic data should be submitted. 

Each of the stratigraphic units located in the zone of saturation should be 

characterized for the hydrologic parameters of hydraulic conductivity (vertical and 

horizontal), specific yield (unconfined aquifer) or specific storage (confined 

aquifer), and effective porosity. Hydraulic conductivity and porosity of aquifer 

material can be determined by using laboratory or field methods. It is 

recommended that all tests that are conducted to define the hydraulic properties of 

each stratigraphic unit be performed in the field. Laboratory tests may be used to 

substantiate field test results but should not be the sole basis for determining 

aquifer characteristics. Only in special cases will the submittal of laboratory analyses 

be considered adequate for describing aquifer characteristics. Literature value 

estimates for these parameters will rarely be acceptable. 

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OSWER Directive 9481.00-6( 

Each of the hydrologic parameters can vary from point to point, even within 

the same aquifer. Therefore, the areal variations of the parameters within the 

stratigraphic units should be characterized. The amount of data necessary to 

characterize a stratigraphic unit will increase with the increasing heterogeneity of 

the unit. As an example, an aquifer of extensive homogeneous beach sand will 

require less investigation than a glacial unit consistinq of lenticular deposits of 

outwash sand and gravel interbedded with clayey till. However, in order to save 

time and effort, the applicant may choose to makE! simplified "worst case" 

assumptions of hydraulic conductivity and porosity. 

There are many field methods for measuring hydraulic conductivity and 

porosity. Hydraulic conductivity is most effectively determined from the analysis of 

pump test data. For units having low hydrologic conductivity, single-well tests are 

generally used (i.e., a slug test). For units having high hydraulic conductivity, multiwell pumping tests are necessary. The pump test methods are normally designed to 

evaluate the transmissivity and storativity (storage wefficient) of the aquifer. 

Hydraulic conductivity is determined by dividing transmissivity by the aquifer 

thickness. More information on determining aquifer characteristics can be found in 

Freeze and Cherry (1979), Kruseman and De Ridder (1979), U.S. EPA (1983a), and 

Walton (1970). 

Different laboratory methods can be used to substantiate field data. Hydraulic 

conductivity may be determined on a core sample of the aquifer by using either a 

constant-head or a falling-head permeameter. A description of the method can be 

found in Todd (1980) and Bouwer (1978). In the laboratory, effective porosity can 

be determined as the ratio of the volume of water yielded by gravity flow to the 

volume of soil or rock material. 

If an aquitard separates two distinct ground-watN zones, then the physical 

and hydraulic characteristics of that aquitard must be provided in sufficient detail to 

illustrate the degree of interconnection between the two aquifers. This 

requirement can be fulfilled by providing the results of an aquifer pump test 

designed to show the effect of the pumping of the deeper aquifer on the shallow 

aquifer. The shallow aquifer will exhibit significant drawdown during the pump 

test if the two aquifers are interconnected. 

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OSWER Directive 9481.00-GC 

A summary of the hydraulic properties of each stratigraphic zone within the 

zone of saturation should be submitted by the permit applicant. This data should 

be provided in a table that includes the aquifer name, stratigraphic zone, vertical 

conductivity, horizontal conductivity, specific yield, transmissivity, and storage 

coefficient. 

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OSWER Directive 9481.00·6C 

CHAPTER IV 

GROUND-WATER FLOW DIRECTION AND QUANTITY 

(40 CFR 264.94(b)(1)(iii) and (2)(iii)) 

The amount or quantity of ground water at a site and the direction in which it 

flows are two essential components of an analysis of the fate and transport of 

hazardous constituents in the ground water. The ultimate fate of contaminated 

ground water is a principal topic of every attenuation-based ACL demonstration 

since a contaminant plume may discharge into and mix with other ground or 

surface waters. This chapter describes methods that can be used to determine 

ground-water flow direction and quantity at a site. The EPA publication GroundWater Monitoring Technical Enforcement Guidance Document (U.S. EPA 1986a) 

may also be useful in making these determinations. However, if a facility is located 

over a relatively complex hydrogeologic system (e.g., fractured rock or karst 

aquifers), setting the POE at the POC may be the only acceptable method for 

establishing the ACL. 

The primary processes that control the migration of contaminants in 

subsurface environments include: 

I. Advection (movement ofthe ground water), 

2. Hydrodynamic dispersion (mixing of ground water having different 

levels of contamination), and 

3. Chemical reactions. 

For ACL purposes, advection is defined as the migration of hazardous 

constituents by actual motion or flow and is generally assumed to be caused by 

natural ground- water flow. Consideration of advection alone presents the worstcase calculations in terms of peak arrival times and concentration strengths. 

Furthermore, qualitative and quantitative evaluation of advection in terms of flow 

pathways is possible. 

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OSWER Directive 9481.00-GC 

The Section 270.14(c) permit requirements specify the submittal of groundwater flow information. This data should be adequate for on-site determinations 

of flow; however, additional data may be required if off-site determinations of 

ground- water flow are needed for the ACL demonstration. The permit applicant 

should evaluate ground-water flow in terms of the flow regime present at the 

facility. Flow from the facility to the water table will generally occur in the 

unsaturated zone, although it may go via surface water. Where subsurface 

heterogeneities are not significant, it is reasonable to assume that flow through the 

unsaturated zone will be predominantly downward. This assumption is justified 

because gravity is the primary force acting on a fluid in the unsaturated zone. 

Once in the saturated zone, dissolved constituents will move with the ground 

water. Evaluation of advective transport in the saturated zone for miscible 

constituents can generally be based on the observed ground-water flow field and 

hydraulic properties (hydraulic conductivity gradient and effective porosity). The 

observed flow field can be determined by a combination of areal water level maps 

and vertical sections showing water levels. 

Calculations of ground-water quantity will require the use of the subsurface 

hydrogeologic parameters described in Chapter Ill. Ground-water quantity can be 

estimated by calculating the porosity of the aquifer. The use of Darcy's Jaw for 

determining ground-water flow quantity is acceptable and can be found in any 

standard ground-water textbook (e.g., Freeze and Cherry (1979)). Darcy's law can be 

used to calculate specific discharge or volume rate of flow through a cross-sectional 

area perpendicular to the flow direction in relatively homogenous systems. 

The determination of ground-water flow rates and directions is simple in 

concept. If the distribution of hydraulic head and the hydrologic properties at the 

site are known, then a flow net or water level contour map in conjunction with the 

use of Darcy's law can be used to determine flow rates and directions. 

The permit applicant should be aware of a number of factors that can make 

accurate determination of ground-water flow difficult. These include: 

I. Low horizontal or relatively flat gradients, 

2. High vertical or relatively steep gradients, 

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OSWER Directive 9481.00-6C 

3. Temporal variations in water levels, 

4. Heterogeneous properties, and 

5. Anisotropic properties. 

In areas of low horizontal gradients, small errors in water level measurements 

or small transient changes in water levels can make determination of flow direction 

and rates difficult. High vertical gradients often exist in surficial units. In recharge 

areas, head decreases with depth; whereas in discharge areas, it increases with 

depth. Often, a shallow water table aquifer may overlie an aquifer of higher 

permeability, resulting in vertical head gradients. A very common mistake is made 

when water level contour maps are constructed using wells or piezometers at 

different depths. In such a case, calculated horizontal flow directions may be 

inaccurate. 

Water levels can vary temporally because of short-term stresses, tidal effects, 

atmospheric pressure variations, seasonal effects, and long-term trends. In 

determining flow direction, the annually averaged water levels are of primary 

interest. Consideration of short-term effects is more important at sites with low 

hydraulic gradients. In evaluating any water level data, the uncertainty introduced 

by neglecting short-term effects must be estimated. Seasonal variations in recharge 

can result in significant water level variations in unconfined aquifers. Artificial 

recharge and certain types of ground-water pumpage often lead to seasonal 

changes in water levels. These changes may occur under both confined and 

unconfined conditions. 

The degree of heterogeneity in aquifers may range from fairly moderate to 

extreme. The potentiometric surfaces or water levels in heterogeneous aquifers are 

not smooth regular surfaces. At the contact between two geologic materials, the 

hydraulic gradient will be discontinuous. For some aquifers, such as fractured rock 

and karst aquifers, the heterogeneity is much more complex. 

Another property of an aquifer is its anisotropy. Hydraulic conductivity is a 

property that is dependent on direction and therefore has three principal 

components. If the principal components are equal, then the aquifer is isotropic. If 

not, the aquifer is anisotropic. For anisotropic aquifers, flow lines are not 

perpendicular to equipotential lines or water levels. Many aquifers display a 

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OSWER Dtrective 9481.00-GC 

horizontal-vertical anisotropy. However, if the two horizontal components of 

hydraulic conductivity a're equal, then, from an areal perspective, flow lines will be 

perpendicular to lines of equal potential. Aquifers that may demonstrate 

horizontal anisotropy include aquifers in fluvial sandstone, fractured rocks, or 

steeply inclined strata. Ground-water flow direction is difficult to determine from 

water level data in these types of anisotrophic aquifers. 

The factors that make the determination of flow rates and directions 

unreliable can often be overcome by an expanded effort in water level monitoring. 

For seasonal variations in water levels, a higher frequency monitoring schedule is 

necessary. For low horizontal gradients, the effects of short-term changes in water 

levels can be analyzed by installation of continuous rec<>rders in selected wells. In 

aquifers having significant vertical gradients, piezometers completed at various 

depths may be required in order to provide a three-dimensional description of the 

flow field. For heterogeneous and anisotropic aquifers, more water level 

monitoring wells and more field tests for hydraulic properties are required. 

The hydrogeologic portion of the ACL demonstration must include an 

adequate description of both horizontal and vertical ground-water flow 

components. This is required because it will help determine where the hazardous 

constituents may migrate. The horizontal ground-water flow description should 

include a flow net based on ground-water elevation measurements taken from 

monitoring wells or piezometers screened at the same elevation in the same 

saturated zone. The monitoring system must be designed to provide reliable results 

of the ground-water flow direction in the zone of saturation. There may be sites 

that will require the applicant to monitor for hazardous constituents at more than 

one ground-water elevation. When this situation occurs, the permit applicant must 

be especially careful to ensure that the monitoring plan is designed correctly. 

Information obtained from analyses of the hydrogeological properties and 

flow direction will allow the calculation of ground-water flow velocity. Well 

identifier codes, well depths, screened intervals, ground-water elevations, and 

sampling data should be presented in tabular form. The flow net data should be 

graphically portrayed on a site map that includes ground-water elevations, 

isopleths, and flow vectors. As discussed before, the ground-water flow velocity can 

be determined by a simple modification of Darcy's equation if the aquifer is 

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OSWER Directive 9481.00-6( 

relatively isotropic. All calculations and assumptions should be included in the 

discussion of flow rates. 

Vertical ground-water gradients and flow should also be described. Facilities 

should have several nested piezometers for vertical gradient determinations. 

Vertical flow gradient will aid in determining discharge and recharge zones, 

aquitard characteristics, and whether the monitoring wells are located and 

screened at the appropriate depths. The data that should be submitted in tabular 

form for each well nest includes well identification code, well depth, screened 

interval, ground-water elevation, and sampling date. All calculations and 

assumptions should be described in detaiL 

Facilities that are located in environmental settings that exhibit temporal 

variation in ground-water flow direction should define the extent to which the flow 

change occurs. The main causes of ground-water flow variation are: 

1. Seasonality of recharge or discharge, 

2. Ground-water withdrawals, 

3. Underground injection, 

4. Surface water elevation changes, and 

5. Artificially induced recharge by basin flooding. 

In cases of seasonal ground-water flow variation, the permit applicant should 

provide information describing those temporal changes in ground-water flow 

direction using records compiled over a period of no less than one year. 

The rate of withdrawal of ground water is an important factor that influences 

ground-water and contaminant movement and exposure to contaminated water. 

In attenuation-based demonstrations, the rate of ground-water withdrawal in the 

vicinity (5 km radius) of the facility should be summarized in tabular form and 

should include well location, depth, type of use, and withdrawal rates. The zone of 

impact created by any major well or well field withdrawal should be identified on a 

site map. The map should include drawdown isolines out to the 30 centimeter 

drawdown leveL Modeling of drawdown curves should use low recharge 

assumptions such as drought conditions. 

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OSWER Directive 9481 .00-6C 

Models 

Although not required for an ACL demonstration, mathematical simulation 

models of ground-water flow and contaminant transpClrt can be extremely useful 

tools for the applicant. Models are more appropriate for relatively simple geologic 

environments where conditions do not vary widely; in complex geologic areas, 

modeling may be less useful. 

The permit applicant is responsible for ensuring that the models used simulate 

as precisely as possible the characteristics of the site cllld the contaminants and 

minimize the estimates and assumptions required. All models used in the 

demonstration should: 

1. Be compatible with the quality and type of input data available, 

2. Have been demonstrated to be applicable to the environmental 

conditions at the site, 

3. Have been subjected to an independent quality assurance audit or to a 

level of professional peer review equivalent to that for publication in a 

scientific or technical journal, 

4. Be internally consistent in the use of boundary and initial conditions, 

time steps, assumptions, and code modifications, 

5. Have fully documented support available to the Agency, and 

6. Be calibrated and verified for the site before being applied in a predictive 

mode. 

As discussed in Chapter II, a two-dimensional model of a ground-water system 

may be used; however, all simplifying assumptions must be justified. Whenever 

possible, input parameters and assumptions should be conservative in nature; 

worst-case scenarios may save much effort. If models are used, the ACL 

demonstration should include tables of the assumptions, the input parameters, and 

any calibration data. 

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