Comprehensive Sabine Watershed Management Plan Report
Table of Contents Appendix G - Responses to TWDB Comments

Executive Summary

1.0 Introduction

2.0 Water Needs

3.0 Existing Surface Water Supplies

4.0 Existing Ground Water Supplies

5.0 Comparison of Existing Supply and Projected Demand

6.0 Additional Supply from Water Conservation

7.0 Potential Surface Water Projects

8.0 Potential Ground Water Resources

9.0 Water and Wastewater Treatment Needs

10.0 Water Quality & Environmental Issues

11.0 Other Water Related Issues

12.0 Information Management and Public Participation

13.0 Recommendations

Appendices

List of Figures

List of Tables

Return to List of Appendices

To date, two sets of comments have been received from TWDB. One set was submitted by Richard Brown of TWDB in July 1999 as preliminary comments. The second set was submitted by Dr. Tommy Knowles on September 23, 1999. Beginning with Richard Brown=s comments, our response to TWDB comments are in italics below.

Richard Brown Comments, July 1999

1. The funding from TWDB needs to be acknowledged in the report.

This has been corrected. The title page reflects that this study was performed in conjunction with TWDB. We have also stated in the introduction which tasks were funded by TWDB (Task 7 - Water Treatment Needs, Task 8 - Wastewater Treatment Needs, and Task 15 - Aquifer Storage and Recovery).

2. Task 20: Mitigation Banking was added after the contract was approved, this seems to be a valuable task but we can not reimburse costs related to this task.

This task was added at SRA=s cost. TWDB is funding only the three tasks listed above and has only been charged for the time and expenses associated with those three tasks.

3. Section 1.3, 4th paragraph speaks to "...most of this water is being reserved for the future use*". Please clarify if the quantity of water is the existing water rights, or is there a different quantity being reserved.

The amount we show as being reserved for future use by an entity is the full amount of their existing water right or contract. Therefore, that water was not considered "available" for other entities.

4. The assumption used here for manufacturing water demand projections is low oil price and no conservation. This is different than the consensus scenario used in 1997 State Water Plan and may not be consistent with the revisions to that scenario currently being requested by the Regional Water Planning Groups.

After looking at the Consensus numbers for manufacturing, they were deemed to be too low to be reasonable in this particular case, so the low oil price, no conservation scenario was used. In this Comprehensive Plan, the future development plan for the basin has been structured in a phased approach so that, if in fact, the manufacturing demand does not materialize, then large amounts of capital will not have been invested to provide for that demand. Chapter 13 of the report explains this in detail.

The water demand projections need to be coordinated through the Water Uses Section of TWDB (contact Butch Bloodworth) so they are consistent with any revisions being requested by the RWPGs.

The projections for this study were formulated at the beginning of this study, which preceded Senate Bill 1 and the Regional Water Planning Groups by more than a year. It is not feasible to require that this study be redone based on SB1 projections.

5. Section 3.4, last paragraph speaks to short term contracts. Senate Bill 1 may have made changes to the Texas Water Code which could impact this paragraph.

Senate Bill One does not change this.

6. Section 5.0, 2nd paragraph speaks to "Ground water supply was estimated from the year 2000 ground water projections*". Please clarify, are supply estimates per county constant for all future decades, and/or are these based on projected use in 2000 (from 1997 State Water Plan or some other use projection) or are these projected supply amounts (from 1997 State Water Plan or some other supply projection).

Groundwater supply estimates per county were held constant for all future decades.

7. Section 10.2.1 appears to be a useful summary of environmental regulations. However, in the Texas General Land Office portion is "Aquifer Recharge Rule" which states that "No permit is required to inject clean water into groundwater aquifers*". Actually such permitting authority resides with TNRCC and such an injection permit (Class V) is required. If surface water is the source, a new or amended water right permit would also be required from TNRCC.

This section has been changed to state that a TNRCC Class V injection permit is required.

 

Tommy Knowles Comments, September 1999

  1. Background: Figure 1.1 does not identify the reservoirs pictured.

Figure 1.1 is intended to give an overall picture of the entire basin. Figure 1.1 has been changed to identify the three reservoirs referred to in this section (Lake Tawakoni, Lake Fork, and Toledo Bend). Chapter 3, which discusses each reservoir in detail, contains figures that identify all of the reservoirs in the basin.

1.2 Sabine Watershed Hydrology: The 12 stream gages referenced in the text on page 1-5 are not located in Figure 1.2.

The 5 key stream gages selected as representative gages have been added to Figure 1.2.

The text should contain a justification of the selection of the 5 key gage locations currently shown in Figure 1.2

The text states that these five gages were selected "based on their location, period of record, and proximity to a rainfall monitoring station."

The maps describing the average annual evaporation and average annual runoff as required in the scope of work were not included in this section. The tables showing time histories of reservoir contents at SRA reservoirs, time histories of rainfall at 4 key rain gages, and seasonal distribution of rainfall and runoff at key locations as required in the scope of work were not included in this section. The text of this section was lacking description of the maps and tables noted as missing.

These maps have already been created and were included in the technical memorandum for Scope Task 2 and in the GIS package. It was decided that this level of detail was not needed in the final report. (Copies of all technical memoranda for this project will be provided to TWDB at the conclusion of the project.)

1.3 Water Rights: On page 1-7, the reference in the text to Iron Bridge Dam does not provide a location.

Reference has been added to describe the location of Iron Bridge Dam.

The Sabine Basin Annual Permitted Use total described in Table 1.1 does not distinguish between annual use permitted volumes committed inside and outside of the Sabine Basin. Of the volume permitted for annual use outside of the Sabine Basin, a distinction should be made in Table 1.1 between volumes permitted to the City of Dallas and other users.

The City of Dallas is the only entity outside of the Sabine Basin that holds water permits in the Sabine Basin. Those permits are for portions of the Lake Fork and Lake Tawakoni yields. Other out-of-basin entities have contracts for Sabine Basin water. Those are detailed in Appendix E. Since Table 1.1 is dealing with permits rather than contracts, a column will be added to show Dallas= portions of water rights that are for use outside of the Sabine Basin, but will not show any contracted amount of water that are used out of the Basin.

The text on pages 1-8 and 1-9 describes water from the Louisiana portion of the Sabine Basin as potentially available; the potentially available volumes should be tabulated in a format similar to Tables 1.1 and 3.3

The volume of water available from Louisiana has not been quantified, and it was beyond the scope of this project to quantify the amount available.

The point of Louisiana-Texas water sales described on page 1-9 should be located on a map.

The Logansport gage has been added to Figure 1.2. Text has been added to refer to this map for the location of Logansport, Louisiana, which is the point of the Texas-Louisiana sale.

 

1.4 Mineral Resources Evaluation: Figures 1.4, 1.5, and 1.6 lack the inclusion of county lines.

County lines have been added.

The first paragraph on page 1-10 references water quality issues associated with mining and energy generating facilities. Chapter 10 should offer greater detail on these issues.

It was determined that there was insufficient information available to make an accurate correlation between water quality and mining and energy generating facilities. Therefore, the text on page 1-10 has been taken out of the report.

2.2 Water Use: As noted on pages 2-2 and 2-3, the scenario for manufacturing water use projections differs from the one used in the Consensus-Based State Water Plan.

After looking at the Consensus numbers for manufacturing, they were deemed to be too low to be reasonable in this particular case, so the low oil price, no conservation scenario was used. The future development plan for the basin has been structured in a phased approach so that, if in fact, the manufacturing demand does not materialize, then large amounts of capital will not have been invested to provide for that demand. Chapter 13 of the report explains this in detail.

Note that any projections to be used for SB1 planning purposes must be approved by the appropriate Regional Water Planning Group(s). Additionally, any proposed changes to the state consensus projections will be review based on the criteria and data requirements described in "Guidelines and Data Requirements for Addressing Revisions of the Consensus-Based Population and Water Demand Projections."

The projections for this study were formulated at the beginning of this study, which preceded Senate Bill 1 and the Regional Water Planning Groups by more than a year. It is not feasible to require that this study be redone based on SB1 projections.

3.0 Existing Surface Water Supplies: Figure 3.1 and Table 3.1 do not indicated which reservoirs are used for water supply and which are used for recreation as referenced in the text on page 3-1.

A sentence was added clarifying that the four recreation lakes referenced in the text on page 3-1 are the Wood County Lakes. With this sentence, no change was necessary in Figure 3.1 or Table 3.1.

3.2.1 SRA Reservoirs and Canal System: Table 3.2 does not include the out of basin portion of allocations for lakes Fork and Tawakoni. It should be clarified whether the demand increase in the Upper Basin which is projected to exceed supply, described on page 1-8 and shown in Table 5.1, is expected to come from the City of Dallas or elsewhere outside of the Sabine Basin.

Table 3.2 shows the available supplies from each water sources, and does not deal with the allocation of supply. Chapter 5 deals with the allocation of supplies to demands. Table 5.1 shows the total amount of water available in each county, then deducts the set amount of exports specified in the permits or contracts (not based on demand, but on permitted or contracted amounts). The demand increase in the Upper Basin, which is projected to exceed supply, is only for in-basin needs. No demands for out of basin entities were analyzed. In the case of Dallas, the specified amounts that are permitted to Dallas in the water rights were assumed to be exported out of basin to Dallas, regardless of what their future demands would be.

4.1 Aquifer Descriptions: The general extent of Sabine Basin aquifers are illustrated in Figure 4.1, however, the figure lacks delineation of the aquifer recharge zones as required in the scope of work.

Figure 4.2 has been added showing the aquifer outcrops which are equivalent to the recharge zones.

Aquifer descriptions include only brief water quality references, which are inconsistent and lack meaningful detail. No figures or discussion was offered to illustrate aquifer layering, as required in the scope of work. References to static water levels were lacking valuation or geo-reference and not included in all aquifer descriptions. No maps or figures to illustrate static water levels were included.

The scope of work instructs the consultant to "review" the above topics and does not call for a detailed description of each. The topics for review were to provide information needed in the required water budget and availability analysis.

Page 4-7, contains the following statement; "A few wells in the basin have been completed in other aquifers, such as the Trinity, Cypress Spring and Cain River. These other ground water sources provide approximately 470 acre-feet per year in the Sabine Basin." The terms Cypress aquifer and Cane River Formation/aquifer represent various water-bearing strata of the Wilcox and Claiborne Groups. With the exception of the Cane River Formation, the various water-bearing strata of the Wilcox and Claiborne Groups were individually discussed in sub-section 4.1. If the terms Cypress Spring and Cain River were intended to refer to the Cypress and Can River aquifers, the annual discharge of these wells should be reassigned appropriately. For clarification of formation and aquifer terminology, please refer to TWDB Report 27 "Ground-Water Resources of Harrison County" and Report 37 "Ground-Water Resources of Sabine and San Augustine Counties." Please refer also to previous comments on aquifer layering.

This statement can be rewritten as follows:

A few wells in the basin have been completed in aquifers that are listed as "other" in Table 4.2. These specific aquifers were not identified due to their relative insignificance within the basin. A minor amount of groundwater is produced from the Trinity aquifer in Collin and Rockwall counties. In Harrison and Sabine counties, the aquifer terminology of Cypress Springs and Cain River have been used in older reports to depict aquifer units that are currently incorporated in aquifer units used in this report. Groundwater associated with the Cypress Springs and Cain River are likewise incorporated into the current aquifer usage. These "other" ground water sources provide approximately 470 acre-feet per year in the Sabine Basin.

4.2 Aquifer Demands: Selected groundwater demands are included in the discussion and Tables 4.1 and 4.2, however, only 1996 historical demands and year 2000 projected demands are offered in response to the scope of work requirements for historic and future groundwater demands.

This section is intended to characterize current groundwater demand. Future groundwater forecasts are combined with surface water demands and shown in Table 5.1.

On page 4-6, attribution is made to TWDB as a source of projected demand data without further specification.

The first line of the 4.2 Aquifer Demand section has been modified to include the underlined text below:

Approximately 48,000 acre-feet per year of ground water is projected by the TWDB in the development of the 1997 State Water Plan, to be used within the Sabine Basin by the year 2000.

7.1 Previously Proposed Reservoirs: Figure 7.3 does not indicate the location of the water quality issues discussed on page 1-10. (Please refer to comments on Section 1.4)

It was determined that there was insufficient information available to make an accurate correlation between water quality and mining and energy generating facilities. Therefore, the text on page 1-10 has been taken out of the report, and there is no need to identify any locations of water quality issues on Figure 7.3.

8.1 Development of Groundwater Supplies: Lacks detail about the potential for ground water development by particular communities or counties within the Sabine Basin. Statements on page 8-1 serve as an example, "The Carrizo-Wilcox aquifer is the most important ground water resource in the Sabine River area and has the greatest potential for future development. Based on a TWDB evaluation, a significant increase of ground water could be attained with proper development." The discussion that follows these statements does not contain additional detail or explanation of what may constitute "proper development".

The scope did not call for that level of detail and the budget for that task did not allow for that level of detail. The budget for the task ($28,500) is only 5% of the total project=s original budget ($553,000).

Additionally, attribution is made to a TWDB evaluation without specification.

See answer to 4.2 above.

8.1.1 Ground Water Availability: Does not offer specific discussion on the actual methodology employed to determine the specific groundwater availability values included in Table 8.1.

No estimate of aquifer storage gain or loss was included. An estimate of aquifer discharge including gains or losses to streams as specified in the scope of work was lacking.

The first paragraph of this section has been moved to Section 4.2.1 of the report and reads as follows:

Ground water availability can be estimated using several different methods, which have varying results. The TWDB developed a ground water model for a large area that included the upper portion of the Sabine Basin. To determine water availability to meet future needs, the model was run assuming all future demand was met by ground water. This resulted in large availability numbers for counties where large demands were projected (e.g., Harrison County was projected to have an annual ground water availability of 183,500 acre-feet per year). These high availability estimates include both effective recharge and the removal of ground water from storage. While the TWDB model does demonstrate that there is a sufficient amount of water contained in the Carrizo-Wilcox aquifer, the model was not run to simulate levels of pumpage that might be considered based on reasonable and practical economic assumptions.

Another method of estimating ground water availability assumes that the only water to be used is a quantity equivalent to the average annual effective recharge. This methodology is the most conservative since these availability estimates do not include the removal of water from storage in the aquifer. This approach allows for the assessment of long-term availability of the aquifer without incurring large water level declines.

For this Plan, the estimated ground water availability in the Sabine Basin is based on a modified water budget approach. The components of the budget consist of input to the aquifer system as recharge, water held in storage within the aquifer, and output or withdrawal from the aquifer as pumpage and spring flow. Annual effective recharge for the aquifers within the Sabine Basin were derived from estimates based on TWDB aquifer analyses and include consideration of input to the aquifer from both precipitation and seepage from streams. Water in storage is based on estimates of saturated thickness and storage coefficient of the aquifer medium. Total discharge from the aquifer includes pumpage and water that is naturally rejected from underground in the form of spring flow.

In quantifying availability, consideration was made concerning the historical use of each aquifer in each county. If water level records suggested a relatively static condition, then annual effective recharge was considered an appropriate availability estimate. However, if the aquifer in a particular county had been or is expected to be heavily used and recharge alone is insufficient to meet forecasted demands, then recharge along with a specified depletion of storage was assigned as availability. The availability estimates for the Gulf Coast, Sparta and Yegua aquifers are based solely on annual effective recharge, while estimates for the Carrizo-Wilcox, Queen City and Nacatoch aquifers include, for some counties, the depletion of a specified amount of water in storage.

Estimated ground water availability from the Carrizo-Wilcox aquifer in the Sabine Basin is based on the annual effective recharge throughout the aquifer extent, and also includes a three-percent per year depletion of storage in most counties. Nacatoch aquifer availability consists of effective recharge in outcrop counties and a combination of recharge and/or storage depletion in the downdip counties of Hopkins and Rains.

Water availability from the Queen City aquifer is limited to effective recharge in Harrison and Rusk counties where recharge is less relative to other counties. In the other counties, effective recharge estimates are significantly higher (Table 4.5) and do not realistically equate to availability. For these counties availability is based on recoverability estimates for the portion of the aquifer with sufficient saturated thickness to support well yields of 200 gpm or more. Availability was estimated by establishing a conceptual well field over the designated area with wells spaced one mile apart and allowed to withdraw water at a rate of 12 hours per day for 365 days. This method allowed for a much more reasonable availability estimate in Gregg, Smith, Upshur and Wood counties. The total amount of water that is determined to be available from the Queen City aquifer in the Sabine Basin is about 32,000 acre-feet per year.

A total of 138,492 acre-feet of ground water per year are estimated to be available in the Sabine Basin. Summaries of these estimates by county and aquifer are shown in Tables 4.4 and 4.5. Of the six primary aquifers in the basin, the Gulf Coast (53,003 acre-feet), the Carrizo-Wilcox (44,820 acre-feet) and the Queen City (32,012 acre-feet) contain 94 percent of the total annual available ground water.

Since there is ample surface water supply already developed in the lower basin, it is unlikely that future well fields in the Gulf Coast aquifer will be developed for regional supply. Ninety seven percent of the calculated availability from the Carrizo-Wilcox is located in the upper basin. The Queen City aquifer, located totally in the upper basin, has the greatest annual water recharge at 137,800 acre-feet per year. However, as previously discussed, much of the water is released from the aquifer to local streams and springs. Proper development of well fields could reduce the amount of lost recharge, but probably could never capture the recharge quantity indicated in Tables 4.4 and 4.5.

8.1.2 Costs: Does not specify estimated cost of either investigating feasibility of groundwater development or actual development of specific resources to meet identified needs. The discussion relies on terms such as: "relatively low costs" or "significantly higher cost" without an identifiable dollar value reference.

The scope did not call for any costs to be identified in specific dollar value. (See answer to comment 8.1 above.)

8.2 Aquifer Storage and Recovery: The conceptual applications of ASR technology for the Cities of Kilgore and Canton, lack justification relative to projected demand increases or the economy of ASR as opposed to other options. The list of potential sites considered for study in Smith, Wood, Rains, and Van Zandt Counties with ranking of the sites as specified in the scope of work was not present in this section. The methodology for ranking of sites considered for study was not included.

The following text will be inserted in this section.

Cities that utilize ground water and surface water within Rains, Smith, Van Zandt, and Wood counties were considered as potential candidates for artificial recharge. Discussions with the staff of the Sabine River Authority also provided information on cities that may be interested in artificial recharge as a water supply option. Kilgore in Smith County, Emory in Rains County, Canton and Grand Saline in Van Zandt County and Quitman in Wood County were considered as candidates. The City of Kilgore was considered a viable option for further study because of its well field in the Carrizo-Wilcox aquifer, the water-level decline(about 70 to 100 feet since 1952) that has occurred in the well field due to past pumping, and the availability of treated surface water from the City=s system. The City of Canton in Van Zandt County also was considered a viable candidate because of the combined surface water and ground water supply and the increase in water demand that is occurring in the City due to growth and the commercial and reselling market served by the City's water supply system. Representatives of Canton and Kilgore also expressed an interest in the feasibility of artificial recharge to help provide additional water supply.

Quitman in Wood County has an adequate surface water supply and does not have the projected increase in demand as other cities. Grand Saline was not selected because treated surface water to the City would have to be provided via pipeline from another city in the area. Emory in Rains County is a town with 963 people and does not represent a large enough potential project to warrant further consideration.

The cities of Kilgore and Canton were selected also because they would represent a study of artificial recharge for a larger city of about 11,000 and the study of artificial recharge of a smaller city with a population of about 3,000. The aquifer conditions for the Kilgore well field in Smith County and for the water wells utilized by Canton indicate that it should be possible to store the water in the aquifer and have it retained there for utilization by the cities. There is very limited pumpage in proximity to Canton and the City of Kilgore well field.

Water usage by the City of Kilgore was 2,950 and 3,095 acre-feet per year (af/y) in 1996 and 1997, respectively. The municipal water demand for Kilgore is projected to be 2,794 af/y, 2,854 af/y, and 2,940 af/y by 2010, 2020, and 2030, respectively. In addition, Kilgore supplies approximately 700 af/y to wholesale municipal and industrial customers. Data for the City of Canton show that water usage was about 649 acre-feet in 1996 compared to 484 acre-feet in 1986. Municipal water demand is projected to be 681 af/y, 679 af/y, and 658 af/y by 2010, 2020, and 2030, respectively. In addition, Canton supplies approximately 100 af/y to wholesale municipal customers.

Aquifer parameters (transmissivity, storage and permeability) were not included as specified in the scope of work. Water demand projections for certain users, as specified in the scope of work, were not included.

Water demand projections for Kilgore and Canton have been added to the text.

The following text regarding aquifer parameters will be added to the report:

Aquifer Parameters - City of Kilgore

Values of transmissivity, permeability and storage coefficient of the aquifer at the City of Kilgore well field have been calculated based on available data. Production Wells No. 1 through No. 9 in the well field screen sands in the Carrizo Sand or in the Carrizo Sand and underlying Wilcox aquifer and at the time of the tests, the aquifers were under artesian conditions. Pumping tests in the well field provide a coefficient of transmissivity that ranges from about 19,000 to 38,000 gallons per day per foot (gpd/ft) with the range in transmissivity values caused by the differences in thickness and permeability of sands screened by the wells. In general, the permeability of sands in the Carrizo Sand is higher than the permeability of the sands in the Wilcox aquifer. The test results show this to be the case and the data indicate an average value of permeability of about 152 gallons per day per square foot (gpd/ft(2) for the sands. Interference drawdown tests indicate an average coefficient of storage of about 0.0002 which is in line with the coefficient of storage values for unconsolidated sand aquifers under artesian conditions.

The specific capacities of the City of Kilgore Wells Nos. 1 through 9 range from 6.4 to 37.4 gallons per minute per foot of drawdown (gpm/ft) and average 19.9 gpm/ft. The specific capacities indicate that the sands screened have good permeability and could be less susceptible to clogging during injection than wells with lower specific capacities.

Aquifer Parameters - City of Canton

Limited data are available on the transmissivity, permeability, and storage coefficient values for the Wilcox aquifer in the vicinity of Canton. Pumping tests have been performed on a number of wells in Rains and Van Zandt that screen the Wilcox aquifer with results provided in Texas Water Development Board Report 169 "Ground-Water Resources of Rains and Van Zandt Counties, Texas". The report gives values of permeability that range from 13.4 to 89.7 gpd/ft(2) and average 38.9 gpd/ft(2). Using an estimated value of permeability of 38.9 gpd/ft(2) and a screened interval for City of Canton Well No. 4 of 107 feet, results in an estimated value of transmissivity of 4,062 gpd/ft. The one-half hour specific capacity of Well No. 4 was measured at 3.3 gpm/ft in 1987. The value of specific capacity is consistent with the estimated transmissivity for the aquifers screened by the well. It is estimated that the coefficient of storage for the sands screened by City of Canton Well No. 4 is in the range of 0.00025 to 0.0004. A pumping test has not been performed on the well with an accompanying observation well to obtain an coefficient of storage based on empirical data. A coefficient of storage of 0.00038 was calculated from an interference drawdown test of wells for the town of Grand Saline which is located about 11 miles from Canton and has wells that screen sands of the Wilcox aquifer.

The two dimensional analytical modeling with regard to recharge and withdrawal specified in the scope was not performed for the Kilgore site. The methodology used for performing two-dimensional modeling of the recharge and withdrawal process for the Canton site was not referenced.

The following text regarding two-dimensional modeling will be added to the report:

Two-Dimensional Modeling of Recharge Effects for City of Kilgore

An aquifer model code was used to estimate the amount of water-level rise that would occur in the recharge wells as a result of artificial recharge. The results are based on 347 gpm (0.5 mgd) being injected through two wells for a period of five months followed by a non-injection period of one day. The two wells selected for the example are Wells 1 and 3 located about 1,700 feet apart in the well field. The aquifer was assumed to have a transmissivity of 18,000 gpd/ft and a storage coefficient of 0.0002. These values are in line with those obtained from pumping tests in the well field with the value of transmissivity being on the conservative side. Based on these assumptions, it was estimated that the water-level rise in the two wells would range from 20 to 30 feet at the end of five months of injection followed by one day of non-injection. During the injection period, the water-level rise in the wells could be in the range of 50 to 100 feet. With the static water level of the wells in the range of 250 to 320 feet, the well water levels during injection periods should remain 150 to 200 feet below land surface.

Two-Dimensional Modeling for the City of Canton Well No. 4

An aquifer model code was used to estimate the amount of water-level rise that could occur in Well No. 4 as the result of artificial recharge. The results are based on 120 gpm being injected through the well for a period of five months followed by a non-injection period of one day. The aquifer is assumed to have a transmissivity of 4,000 gpd/ft and a storage coefficient of 0.00025. These values are estimated are based on pumping test data from wells in Rains and van Zandt counties and on the estimate of transmissivity for Well No. 4. Based on theses assumptions, it is estimated that the water-level rise would range from 15 to 20 feet during five months of injection followed by one day with no injection. During the injection period, the water-level rise in the well could range from about 70 to 110 feet and with a static water level in the well of about 150 feet the wells water level during injection could remain 40 to 80 feet below land surface.

8.2.1 Preliminary Cost Estimates for ASR: The report lacks a complete summary of all costs specified in the scope of work i.e. estimated cost of SRA system operation. Non-quantified costs for ASR system operation and maintenance are referenced to conclude that application of ASR would be economically feasible. A conclusion of ASR economic feasibility should be supported by competitive economic justification of ASR against other potential supply/distribution options including all associated costs.

The current text has been replaced with the following:

Preliminary Cost Estimate for the City of Kilgore

Further studies and pilot testing of ASR are the next steps in assessing the feasibility of a recharge project. The chemical compatibility of the aquifer water and of the treated surface water should be studied and geochemical models used to help determine if chemical plugging of the well and aquifer may occur as the result of artificial recharge. The estimated cost is about $4,000 to $5,000 for collecting samples from the well and surface water supply, performing chemical analyses, and geochemical modeling. Pilot testing should be performed using probably Well No. 3 (34-48-202) to evaluate the aquifer response and well response to the injection of water.

At the ground storage facilities located in Kilgore, it is estimated that a small 500 gpm pump station would be required to pump surface water to the well field ground storage tank. It is estimated that the pump and motor, electrical equipment and piping modifications required at the ground storage tank in Kilgore could cost in the range of $40,000 to $50,000.

Piping and valving modifications and possibly a booster pump and motor and electrical controls would be required at the ground storage tank in the well field to route water back to Well No. 3. Minor piping modifications should be required at Well No. 3, along with installation of a filter or strainer, to route water down the well using the existing discharge piping and pump column assembly. It is estimated that the piping modifications, pump and motor and electrical costs in the well field could be about $40,000.

With the water delivery modifications completed at the ground storage facilities in Kilgore and in the well field and with the piping modifications performed at probably Well No. 3, pilot testing in the well field could begin. Pilot testing would help assess the rate at which the well will accept water and the response of the aquifer to the injection. The pilot testing would include injecting water and subsequently pumping it from the well and possibly repeating the sequence a number of times. It is estimated that the cost of pilot testing could be in the range of about $15,000. If the results of the pilot testing are satisfactory, Well No. 3 could be permanently equipped for ASR and additional booster pump and piping modifications could be completed to help automate the injection of water. Other wells in the well field also could be pilot tested as candidates for ASR. Considering all the above items, the total capital and pilot testing costs for ASR in Kilgore would range form $99,000 to $110,000.

Operating and maintenance costs are estimated as follows:

1. Electric power cost to pump water from Kilgore to well field for 175 feet of lift (500 gpm flow rate).

 

6.64 per 1,000 gallons

2. Labor cost at 4 hours per day at $20 per hour for 720,000 gallons of injection per day.

 

11.14 per 1,000 gallons

3. Treated surface water cost estimate from City of Kilgore

 

$1.32 per 1,000 gallons

4. Electric power cost for 375 feet of lift to pump water from well.

 

14.24 per 1,000 gallons

5. Well Maintenance/Cleaning ($15,000/two years with 5 months of injection per year at 500 gpm or 0.72 mgd.

 

6.64 per 1,000 gallons

Total O&M Cost

 

$1.71 per 1,000 gallons

If successful results are obtained during pilot testing and the artificial recharge system is enlarged to inject more than 500 gpm, then the booster pump facilities in Kilgore and at the well field would be expanded along with piping and monitoring modifications at additional wells. To increase the size of the system to handle about 1,050 gpm, it is estimated that it could cost an additional $150,000 to $200,000. The expenditure would be about evenly divided between facilities at the ground storage tanks in Kilgore and facilities modifications and additions in the well field. Utilization of an artificial recharge program would delay the construction of the next surface water treatment module of 3.5 million gallons per day. The estimated cost of that additional capacity is about $2.8 to $3.5 million.

The preliminary cost estimates are for a conceptual design of an ASR project. Pilot testing is required to help assess if ASR is a feasible water supply option. An economic comparison between a conceptual ASR project and other water supply options that may be considered by Kilgore is beyond the present scope of the study.

Preliminary Cost Estimate for the City of Canton

Further studies and pilot testing of ASR are needed to help assess the feasibility of a recharge project. The chemical compatibility of the treated surface water and the aquifer water should be studied and geochemical models used to help determine if chemical plugging of the well and aquifer may occur as the result of artificial recharge. It is estimated that it could cost about $4,000 to $5,000 for collecting samples from the well and surface water supply, performing chemical analyses, and for geochemical modeling. Pilot testing should be performed using Well No. 4 (37-26-407) to evaluate the aquifer response and well response to the injection of water.

Piping and pump modifications will be required at Well No. 4 to facilitate the injection of surface water. The well pump should be removed and small diameter injection tubes, probably no greater than 2 inches in diameter would be installed to extend below the static water level. The injection tubes would be connected to the well discharge piping and valves and a filter or strainer installed so that water could be routed from the distribution system to the injection tubes. Pump foundation and discharge head modifications may be required to perform the piping modifications. Safety equipment such as a high water-level cut off switch may be required to help insure that the water level does not rise too high in the well. It is estimated that the pump removal and reinstallation, injection tube installation, piping modifications, strainer, and electrical modification at Well No. 4 could cost about $30,000.

Following completion of the geochemical studies and the equipping and modifications at Well No. 4, pilot testing could begin. Pilot testing would help evaluate the rate at which the well will accept water and the response of the aquifer to the injection. Several cycles of injecting water and subsequently pumping it from the well could be required during the pilot testing phase. It is estimated that the cost of the pilot testing could range from about $10,000 to $15,000. If the pilot testing provides satisfactory results, Well No. 4 could be equipped on a permanent basis for ASR. Considering all the above items, the total capital and pilot testing costs for ASR in Kilgore would range form $44,000 to $55,000.

Operating and maintenance costs are estimated as follows:

1. Electric power cost for 270 feet of lift to pump water from well.

 

10.24 per 1,000 gallons

2. Labor cost at 2 hours per day at $20 per hour for 144,000 gallons of injection per day.

 

27.74 per 1,000 gallons

3. Treated surface water.

 

$1.30 per 1,000 gallons

4. Well Maintenance/Cleaning ($10,000/two years with 5 months of injection per year at 100 gpm or 0.144 mgd.

 

22.64 per 1,000 gallons

Total O&M Cost

 

$1.91 per 1,000 gallons

The study of the feasibility of artificial recharge would include, as mentioned previously, performing pilot studies, followed by artificial recharge using Well No. 4. Assuming artificial recharge using Well No. 4 is successful, the City could consider drilling additional wells at locations compatible with its distribution system to inject water into the Wilcox aquifer.

Utilization of artificial recharge to provide water to meet peak demands should help delay the expansion of the existing surface water treatment plant that is rated to provide 2 million gallons per day. Expansion of the plant, which could occur within the next 5 years, would be to a capacity of 4 million gallons per day. The estimated cost for expansion is about $1.6 to $2.0 million.

The preliminary cost estimates are for a conceptual design of an ASR project. Pilot testing, as stated previously, is required to evaluate the feasibility of the ASR option. An economic comparison between a conceptual ASR project and other water supply options that may be considered by Canton is beyond the present scope of the study.

10.1.2 Watershed Influences on Water Quality: The superfund site referenced in Table 10.2 is not discussed relative to water quality implications in the text and is not located on the map.

Table 10.2 has been removed. The associated paragraphs in this section were intended to describe the Subwatershed Approach as developed by the Sabine River Authority. More recent water quality conditions for each segment are presented in subsequent sections.

Figure 10.8 should be further enlarged to allow greater clarity of detail sections to allow identification of industrial discharge location.

This figure will be enlarged to an 11"x17".

10.2.2 Existing Conditions: Table 10.3 listing Endangered and Threatened Species Potentially Occurring in the Counties of Proposed Reservoir Development is cited without a date, for both state and federal species listings. Table 10.3 should include the most current available listing of species available.

Dates have been added to the appropriate citations in the reference section of the document.

10.2.4 Recommendations for New Reservoir Development: Table 10.5 on page 10-23 should be expanded in scope to allow greater clarity of the assessment of the relative risk by category (i.e., threatened/endangered species, archeological/cultural resources, bottomland hardwoods, etc) associated with development of specific projects.

It was determined that there is insufficient data available to quantify the risk by category between specific project sites. Table 10.5 presents a relative ranking of the overall risk for each project site and a list of the issues associated with that site. More detailed information about project sites with respect to each category is presented in sections 10.2.2 and 10.2.3. Further study would be necessary to produce quantifiable information which would be directly comparable between project sites.

 

Attachment 2 Responses:

The following items are Scope of Work deliverables. They were not included in the Draft Final Report and must be submitted for review prior to delivery of the Final Report in order to meet contractual requirements.

Task 2

1. GIS map showing average annual evaporation in the Sabine Basin.

Included in Task 2 Technical Memorandum.

2. GIS map showing average annual runoff in the Sabine Basin.

Included in Task 2 Technical Memorandum.

3. Table showing time histories of SRA reservoir contents

Included in Task 2 Technical Memorandum.

4. Table showing time histories of rainfall at 4 key rain gages.

Included in Task 2 Technical Memorandum.

5. Table showing seasonal distribution of rainfall and runoff at key locations.

Included in Task 2 Technical Memorandum.

Task 3

6. Delineation of aquifer recharge zones.

This has been added as Figure 4.2.

7. Figures and discussion of aquifer layering and hydraulic connection.

See response to comment 4.1 above.

8. Estimates of aquifer discharge (pumpage and gains or losses to streams).

See response to comment 8.1.1 above.

9. Estimates of gains or loss of aquifer storage.

See response to comment 8.1.1 above.

10. Tabulation of historical and future groundwater demands.

1996 historical demands were presented and future demands were held constant at year 2000 demands.

Task 4

11. Table showing the existing water rights in the Sabine Basin in Louisiana.

Louisiana has no formal water rights allocation system therefore Louisiana water rights could not be listed in a table.

Table 15

12. Description of the above items in the text.

Text describing all new tables and maps has been added.

13. Aquifer parameters (transmissivity, storage, permeability) for ASR evaluation-Task 15.

See response to comment 8.2. An entire section has been added on this.

14. Water demand projections for certain groundwater users for ASR evaluation-Task 15.

See response to comment 8.2. Projected demands for Kilgore and Canton have been added.

15. Listing of potential recharge sites in Smith, Wood, Rains and Van Zandt Counties.

See response to comment 8.2. All potential sites have been listed.

16. Ranking of ASR sites selected for study.

See response to comment 8.2.

17. Two-dimensional analytical modeling for ASR recharge and withdrawal rates.

See response to comment 8.2. An entire section of text has been added on this.

18. ASR operating cost estimates.

See response to comment 8.2.1. Estimated operating and maintenance costs have been included.