Alternatives D and E
Description
Description of Alternatives D (CTO with weir) and E (CTO without weir) from 2024 USACE Draft Environmental Impact Statement (DEIS). Page numbers reference the 2024 DEIS Main Report unless otherwise specified.
Various combinations of features were evaluated to form a “Combination Thereof” (CTO) Plan with or without a new weir (Alternatives D and E).
The CTO Plan could include various combinations of the following:
Mitigation features:
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Alternative D (CTO w/weir)

Estimated project first cost: $487-$655 million
Net benefits: $8.2 million-$1.6 million
Benefit Cost Ratio: 1.4 to 1.1
Alternative D includes "Channel Improvements" and a weir/dam. The weir/dam included in this Alternative does not provide any flood control benefits, and construction of the weir necessitates additional pumping needs at existing levees as well as seepage protection on existing levee features upstream of the weir. The proposed weir would result in an expanded, year-round recreational water body capable of supporting recreational facilities. The potential recreational opportunities could include boat ramps, camping areas, fishing piers, trails, or wildlife viewing areas.
Net benefits: $8.2 million-$1.6 million
Benefit Cost Ratio: 1.4 to 1.1
Alternative D includes "Channel Improvements" and a weir/dam. The weir/dam included in this Alternative does not provide any flood control benefits, and construction of the weir necessitates additional pumping needs at existing levees as well as seepage protection on existing levee features upstream of the weir. The proposed weir would result in an expanded, year-round recreational water body capable of supporting recreational facilities. The potential recreational opportunities could include boat ramps, camping areas, fishing piers, trails, or wildlife viewing areas.
Alternative E (CTO without weir)
Estimated project first cost: $399-$508 million
Net benefits: $6.8-$2.4 million
Benefit Cost Ratio: 1.4 to 1.1
Alternative E includes "Channel Improvements" without a weir/dam. The "Channel Improvements" of Alt E would provide the same level of flood risk management and flood inducements as Alternative D. The weir in Alternative D does not provide flood risk management.
(It is unclear why recreational opportunities were not presented as a feature of this Alternative.)
Net benefits: $6.8-$2.4 million
Benefit Cost Ratio: 1.4 to 1.1
Alternative E includes "Channel Improvements" without a weir/dam. The "Channel Improvements" of Alt E would provide the same level of flood risk management and flood inducements as Alternative D. The weir in Alternative D does not provide flood risk management.
(It is unclear why recreational opportunities were not presented as a feature of this Alternative.)
The following options were removed from the list of potential features included in a CTO Plan:
- Clean out and sustained maintenance of tributaries: This feature was removed upon identifying that this work is being undertaken by the NRCS, State and other local entities through the Mississippi Watershed projects.
- Levee setbacks: This feature was determined to provide limited flood risk reduction benefits.
- Demolition of the existing weir at J.H.Fewell Drinking Water Plant: Demolition of the existing weir is not needed as the existing weir is submerged and does not impede water flow. The existing weir would also be necessary to maintain adequate water supply should a new weir not be constructed.
Features (CTO could include various combinations)
"Channel Improvements"

"Channel Improvements" consist of excavating the Pearl River from River Mile 285 to River Mile 294 to improve conveyance. 1,016 acres (853 acres above the proposed weir, and 163 acres below the proposed weir) would be excavated. The width of excavation would range from 500-2,600 feet, and the material excavated from the floodplain and channel overbanks would range from 11.3-14.1 million cubic yards. "The existing river channel would not be widened, instead excavation of the overbank areas would occur." PDF page 145. Flood Risk Management would be achieved by lowering of the channel overbanks to improve conveyance of water through the project area. The excavation would provide reduction of flood elevations not only within the excavation area, but for over 8 miles upstream. The excavated material would be used to create land areas from 6.5-88 acres.
Weir/Dam

The Alt D (CTO with weir) plan includes building a weir/dam at River Mile 286.5 to create a "Lake Surface Area" of 1,706 acres. The weir/dam would be built to an elevation of 256 ft, 6 ft higher than the current weir at J.H. Fewell Drinking Water Plan. The weir would not provide any flood control benefits. Portions of the weir would be submerged during normal flow allowing excess water to pass downstream. Water would pass over the weir with inflow into the lake approximately equaling outflow at any given time. The current weir at the J.H. Fewell Drinking Water Plant would remain in place. A fish ladder would accompany the dam design to allow for fish passage over the dam. The DEIS does not contain any specific information about the cost or design of the weir/dam or fish passage.
Canton Club Levee
The Canton Club Levee is a levee segment of approximately 1.5 miles proposed on the west bank of the Pearl River in northeast Jackson. This area is bounded by North Canton Club Circle to the north and by Beechcrest Drive to the south. This levee would provide additional flood risk reduction for approximately 100 acres of high density developed neighborhoods and reduce flood risk for over 250 homes.
"All of the structures in this subdivision would no longer flood from a cumulative 100-year event." PDF page 241. Cost estimate for the Canton Club Levee is $10 million. |
Non-Structural Component
The non-structural component is included as mitigation for flooding caused by the project. 52 structures (43 residential homes and 9 other structures) located in federally-designated "disadvantaged communities" will experience first-floor flooding of 5" or greater caused by the CTO Alternative. (source: PDF pages 243-244). Most of these structures are located south of I-20, in South Jackson (Ward 7) and Richland. (Map: 2024 DEIS, Figure 4-13). Owners of these structures, plus the owners of 8 structures that will not receive flood risk reduction by the CTO, could be offered flood reduction measures such as elevation, floodproofing or voluntary buyouts.
Adverse Impacts
"Sacrifice Flooding": Improved conveyance of the river through Jackson will force more water on communities downstream of the project. The DEIS projects that this flood stage increase will be felt up to 32 miles downstream of the project.
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Water Quality and Drinking Water Supply: Adding a large weir could increase sediment loads enough to alter the river water chemistry and induce failure at the existing J.H. Fewell Drinking Water Plant. (source: PDF page 201) The new weir and channel improvements could disturb the known Hazardous Toxic Waste Sites (HTRW) enough to cause probable exposure to toxic contaminants within the ponded area at the inflow to J.H. Fewell Drinking Water Plant. (source: PDF page 201). "Additional study could be needed to determine the best methods of design and construction to limit the impact to potable water throughout the system in respect to contaminant retention due to pooling and sediment loading prior to treatment." PDF page 202
Mitigation: A USACE 2023 internal presentation states: “Identification of lands ongoing for terrestrial mitigation, extremely challenging (if not impossible) to mitigate riverine impacts of this proportion. Experts agree that restoring large systems such as this or even compensating for such great function and habitat loss to a truly desirable condition (as existed pre-disturbance) is impossible to achieve. Impoundment removal seems to be the national trend, due to significant adverse impacts of impoundments on river systems for natural resources and humans.” The USFWS estimated in its Fish and Wildlife Coordination Act Report: "Preliminary analysis shows total mitigation costs (based on bank credit purchase) for forest types and palustrine habitat could exceed $1 billion, which excludes riverine mitigation costs. We expect riverine mitigation to be costly since both function and habitat loss need to be compensated. Therefore, costs would greatly exceed $1 billion." (source: 2024 USACE DEIS, Appendix J, PDF page 44)
Relocations or Removal Actions Required:
High Cost of Alt D (CTO with Weir):
Costs to Rankin Hinds Pearl River Flood and Drainage Control District, the Non Federal Sponsor (NFS):
Harm to endangered and threatened species: Threatened, endangered, and protected species to be assessed: Gulf sturgeon, Pearl River map turtle, ringed sawback turtle, alligator snapping turtle, LA pigtoe mussel, tricolored bat, monarch butterfly, and bald eagle. The CTO Alternatives require Endangered Species Act avoidance and minimization features, and the creation of new habitat mitigation areas to offset losses within the project’s construction footprint areas.
Mitigation: A USACE 2023 internal presentation states: “Identification of lands ongoing for terrestrial mitigation, extremely challenging (if not impossible) to mitigate riverine impacts of this proportion. Experts agree that restoring large systems such as this or even compensating for such great function and habitat loss to a truly desirable condition (as existed pre-disturbance) is impossible to achieve. Impoundment removal seems to be the national trend, due to significant adverse impacts of impoundments on river systems for natural resources and humans.” The USFWS estimated in its Fish and Wildlife Coordination Act Report: "Preliminary analysis shows total mitigation costs (based on bank credit purchase) for forest types and palustrine habitat could exceed $1 billion, which excludes riverine mitigation costs. We expect riverine mitigation to be costly since both function and habitat loss need to be compensated. Therefore, costs would greatly exceed $1 billion." (source: 2024 USACE DEIS, Appendix J, PDF page 44)
Relocations or Removal Actions Required:
- Relocating 4-5 utility transmission lines
- Bridge countermeasures
- Mitigating potential HTRW (Hazardous, Toxic, Radiological Waste Sites) and other hazardous waste sites within the floodplain. USACE is prohibited from undertaking HTRW work on behalf of the Rankin Hinds Pearl River Flood and Drainage Control District (the Non Federal Sponsor). "Consideration may be given to designating an HTRW avoidance alternative as the National Economic Development plan when costs and risks of response actions are uncertain." PDF pages 94-95.
High Cost of Alt D (CTO with Weir):
- Projected First Cost for Alt D (CTO with weir): $487-$655 million
- Maximum Project Cost Limit: $440 million (source: Commander's Report, page 5) (*An increase in the authorized project cost would require approval from Congress)
- Federal Cost Share Appropriation: $221 million (appropriated in Oct 2022)
Costs to Rankin Hinds Pearl River Flood and Drainage Control District, the Non Federal Sponsor (NFS):
- **The Non Federal Sponsor (NFS) shall contribute 35 percent of total project costs. (Source: Commander's Report, pages 13 and 14) The Drainage District has not indicated how they will pay for their portion of the project costs.
- 100% of the costs for remediation of the Hazardous, Toxic, Radiological Waste (HTRW) Sites in the project area. The NFS shall be solely responsible for the performance and costs of cleanup of the HTRW, including the costs of any studies and investigations.
- The NFS shall acquire the real property interests that the Government has determined are required for the construction, operation, and maintenance of the Project.
- The NFS shall perform or ensure the performance of the relocations necessary for construction, operation, and maintenance of the Project
- In addition, the Drainage District will be responsible for Estimated Annual Operation and Maintenance Costs of $729,936-$891,122/year for Alt D (CTO with weir) or $196,976-$421,372/year for Alt E (CTO without weir). Local Levee Board revenues are obtained through a 4.75-mil tax assessment on properties protected by the levee system. The majority of the tax revenue comes from properties located in Rankin County. The state-owned properties on the Jackson side of the Pearl River do not pay taxes.
Harm to endangered and threatened species: Threatened, endangered, and protected species to be assessed: Gulf sturgeon, Pearl River map turtle, ringed sawback turtle, alligator snapping turtle, LA pigtoe mussel, tricolored bat, monarch butterfly, and bald eagle. The CTO Alternatives require Endangered Species Act avoidance and minimization features, and the creation of new habitat mitigation areas to offset losses within the project’s construction footprint areas.

Loss of Public Lands: 78 acres, 16% of LeFleur’s Bluff State Park, Jackson’s only public access to the Pearl River and a popular recreation area, would be excavated and permanently under water, according to the map published in the 2024 USACE DEIS. The CTO "Channel Improvements" feature would dramatically alter the hydrology of the park's Mayes Lake and its hardwood forests and cypress sloughs.
LeFleurs Bluff State Park has been the recipient of $1,422,999 in Land Water Conservation Act grant funding. (not adjusted for inflation) A condition of the grant is that: "No property acquired or developed with assistance under this section shall, without the approval of the Secretary, be converted to other than public outdoor recreation uses."
LeFleurs Bluff State Park has been the recipient of $1,422,999 in Land Water Conservation Act grant funding. (not adjusted for inflation) A condition of the grant is that: "No property acquired or developed with assistance under this section shall, without the approval of the Secretary, be converted to other than public outdoor recreation uses."
Additional studies required: Only 4 years ago, some Jackson community members had 4 feet of water in their homes. With rapidly rising flood insurance costs and the threat of further flooding, residents literally cannot afford to wait. The CTO Alternative will require a lengthy process of additional NEPA (National Environmental Policy Act) studies and analysis. Many critical studies and analyses are missing or incomplete in the 2024 USACE DEIS. The USACE states in the document that many of the studies required NEPA process will not be conducted until the Pre-Construction, Engineering, and Design (PED) Phase, which occurs after the USACE Assistant Secretary of Civil Works makes his Record of Decision about the project. A few of the further required studies are listed below. None of these studies will be required for Alternative A1.
- Mitigation plan (to be developed during PED and included in a subsequent NEPA document)
- 404(b)(1) Clean Water Act Analysis (to be conducted during PED)
- Bridge countermeasures to prevent failure of main channel bridges (major evaluation will be a PED effort)
- Sedimentation study (to be conducted during PED) "During design, additional study and verification would be needed to confirm that adding a large weir would not induce sediment loads to alter the incoming chemistry in such a way to induce failure at the existing J.H. Fewell Plant or any other proposed structure along the newly ponded area. A sedimentation study has been proposed to be completed during the PED phase of this study." (PDF page 201)
- Velocity Analyses (to be conducted during PED)
- Utility Relocation Plan (to be conducted during PED) "It is estimated that 5 to 6 of these lines will require additional utility relocation costs. Coordination with the operating entity to determine specific requirements of each transmission line will be conducted during PED." (PDF page 124)
- LeFleurs Bluff State Park Mayes Lake work (to be determined during PED) "Mayes Lake (Sta. 310+00±) may need tie-in work to maintain its current level. A determination about the tie-in work would be made during the PED phase." (PDF page 130)
- Railway Bridge Planning (to be conducted during PED) "There are a total of 2 active railroad bridges within the project area. All efforts would be made to avoid, monitor, and protect these structures. Additional modeling is required to validate these assumptions during PED. If avoidance is not possible, then coordination with the operating entity to determine specific requirements of each railway bridge will be conducted during PED."(PDF page 131)
- Fish Passage Design (coordinated during PED) "The fish passage design will be coordinated with The Service and state agencies during the PED phase." (PDF page 135)
- Borrow Area Analysis (investigated during PED) "Borrow opportunities would be further investigated during PED and a supplemental NEPA document would be prepared at that time." (PDF page 137)
- Hazardous Toxic Waste Site mitigation (to be determined during PED)
- Historical and Cultural Site Assessments (adjusted during PED) "The Jackson MSA has significant historical and cultural site presence, final site locations would be adjusted during PED following completion of cultural resource surveys." (PDF page 147)
- Habitat Mitigation (completed during PED) "Habitat Mitigation would be achieved by implementing Corps constructed mitigation projects and/or purchasing of mitigation bank credits. Further planning and analysis would be completed during PED to determine which strategies, stand alone or combined, would fully compensate for habitat impacts." (PDF page 155)
- CTO Implementation (additional analysis could be required during PED) "To implement multiple flood risk management features and a more comprehensive solution, additional authority is required either an increase in the total authorized project cost under Section 3104 or a programmatic authority to implement flood risk management features in the Pearl River Basin similar to CAP Section 205 projects. Additional analysis and design, feasibility level decision documents, and supplemental NEPA documentation would be required during the PED phase if such solutions are recommended." (PDF page 256)
- Levee Studies (calculated in PED) "The currently proposed Alt C being evaluated by USACE does not include any alignment or height changes to the existing Jackson Fairgrounds Levee." "It is also unknown whether the proposed alternative will change the overtopping location on the levee system. This overtopping frequency and location would need to be calculated in PED phases." (PDF page 263)
- Impacts of CTO on tributary flooding (the DEIS states that Alt C would increase flooding along the tributaries but does not discuss CTO impacts on tributaries). “It is recommended that a survey of tributaries and structures along the tributaries be incorporated into the model to better estimate flooding and impacts along tributaries.” (PDF page 247)
- Water quality impacts – additional modeling/data required to determine if either CTO is “viable”
- Storm Water Pollution Protection Plan (SWPPP) (during PED, downstream impacts will be assessed and coordination with the resource agencies will take place)
- Water supply impacts, "Depending on the method and means of selected features additional study could be needed to determine the best methods of design and construction to limit the impact to potable water throughout the system in respect to contaminant retention due to pooling and sediment loading prior to treatment." (PDF page 202)
- Formal Endangered Species Act consultation on CTO (must be reinitiated)
- Weir design
Pearl Riverkeeper asks that everyone make his or her own decision regarding the Pearl River Flood Risk Management Project using sound science and engineering. We encourage the review and thorough analysis of all available information. We welcome comments and feedback. Please email Pearl Riverkeeper or visit our Facebook for comment space. Our publishing, or re-publishing, of anyone else's research or opinions is not an endorsement on our part of those conclusions.