THE MARGARET CREEK SUBDISTRICT OF
THE HOCKING CONSERVANCY DISTRICT
The Common Pleas Court established the Margaret Creek Conservancy District (MCCD) in November 1963. The primary purpose for forming the MCCD was to act as the local sponsor to implement the Work Plan prepared by the U.S Department of Agriculture – Soil Conservation Service (SCS) for the 60 square mile Margaret Creek watershed located southwest of Athens. Margaret Creek is a major tributary of the Hocking River. The February 1965 Work Plan as amended called for the construction of five small flood detention reservoirs, to:
- Reduce flooding
- Improve downstream bridge capacity
- Store water for municipal supply
- Provide RecreationReduce soil erosion
- Improve local economic conditions
The four dams, currently owned and operated by the Margaret Creek Subdistrict, were completed between 1966 and 1972 at a cost of $728,500. Using the ENR Cost Index this equates to a 2009 construction cost of $4,642,000. In 1989 the Conservancy Court for the MCCD ordered the merger of the Margaret Creek District with the Hocking Conservancy District as a Subdistrict of the Hocking Conservancy District.
2. Project Benefits
The system of five dams constructed by the SCS, of which four are operated and maintained by the Margaret Creek Subdistrict, provide a number of benefits to property owners in the watershed and to residents of Athens County. The primary benefit is that they control the runoff from a large portion of the Margaret Creek Watershed and in doing so reduce the magnitude and frequency of flooding to property and infrastructure. This in turn reduces the inconvenience of road closings, damaged roads and bridges, emergency response to flooded homes and business and clean up costs. It also reduces the cost to local governments to replace and enlarge bridges.
While currently not used for municipal water supply, the lakes also provide the opportunity for future water supply requirements or as a back-up source during water emergencies. Local residents can also enjoy the many varied recreational opportunities at Lake Snowden and Fox Lake. The dams store sediment, which reduces the cost of expensive sand bar removal downstream. Finally, the original construction of the dams and the proposed safety improvements to two of the structures produce economic benefits to the local community by bringing in a significant amount of federal dollars, providing local construction jobs and the purchase of local materials and equipment, all of which benefits the local community.
3. Dam Information
In 1983 the Ohio Department of Natural Resources classified Site #6, Fox Lake Dam, as a Class 1 High Hazard structure because of its height, pool area and potentially impacted downstream development. In 1990, Site #1, Meeks Lake Dam, was also classified as a Class 1 High Hazard structure. As a result, it was necessary to develop an Emergency Action Plan (EAP) for each site, which evaluates the potential downstream flood wave if a dam failure should occur. In addition, the US Natural Resources Conservation Service (NRCS) in 2009 and 2010 prepared Assessment Reports on remediation required at Sites #1 and #6 to protect the structures from the Probable Maximum Flood (PMF). The estimated cost to upgrade the two structures to pass the PMF is between $1.8 and $2.1 million. Applications for federal dam rehabilitation assistance were submitted in 2007. These grants require a 35% local share from the local project sponsor, which in this case is the Margaret Creek Subdistrict. The local match could exceed $750,000. If funding is not obtained to meet the State Dam Safety requirements, the two dams may have to be breached and would no longer provide flood control, water supply, recreation, environmental or economic benefits.
4. Operation & Maintenance Project Plan
a. Dam Upgrades - Several alternatives were evaluated by NRCS in their Rehabilitation Assessment Reports for Site #1 and Site #6. These included various combinations of raising the dams and enlarging the emergency spillways to accommodate the Probable Maximum Flood (PMF). The PMF is defined by the Ohio Department of Natural Resources as, “the flood that may be expected from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in a drainage area.” For Athens County Ohio the Probable Maximum Precipitation (PMP) for a 6-hour duration storm over a 10 square mile area is projected to be 27.2 inches of rainfall. This is the magnitude of the design storm rainfall that must be stored within the reservoir or pass through the emergency spillway to ensure that the dam is not overtopped by the PMF. The Probable Maximum Flood is the dam safety standard for high hazard dams under Ohio law.
For the Meeks Lake Dam, NRCS estimates that the most viable remediation would include adding a new 180-foot wide Roller Compacted Concrete (RCC) emergency spillway in the center of the dam. This alternative would cost an estimated $770,000 to $890,000, of which 35%, as much as $312,000 would be the responsibility of the Margaret Creek Subdistrict.
For the Fox Lake Dam, NRCS estimates that the least costly remediation would involve construction of a 200-foot wide roller compacted spillway. The estimated cost of this alternative is between $1,000,000 and $1,250,000. The local share could be as much as $438,000.
The local cost for the two dam remediation programs would then be approximately $750,000. This Project Plan includes that amount financed over 20 years at 4% interest or $55,200 per year. Should local matching funds not be available the two structures may have to be breached thus eliminating downstream flood reduction, recreation, erosion and sediment control benefits.
b. Operation and Maintenance (O&M) – O&M of the Margaret Creek Subdistrict entails periodic inspections of the dams along with the inlet and outlet structures, woody plant removal, fence repairs and clearing, debris removal, mowing the dam and adjoining property, rodent control, and repairs to gate valves.
The NRCS and ODNR also periodically inspect the four dams to ensure that they meet state and federal dam safety regulations. The current cost of operation and maintenance of the four structures is $10,000 per year. This cost is increased by 3% per year in the Plan to $13,500 per year to include inflation over the 20-year life of the Plan.
c. Maintenance personnel from the Hocking Conservancy District utilizing equipment purchased by the District perform the operation and maintenance of the MCCD. To reimburse the HCD for this equipment use, the number of hours this equipment is utilized to maintain the MCCD is recorded and the HCD is reimbursed for this use at a standard hourly rate. This equipment includes an extending arm mower to mow the steep slopes of the dams, tractors with Bushhog mowers, weed eaters, chainsaws, etc. The current cost for equipment use is $4,000 per year, which is updated in the Project Plan by 3% inflation.
d. Capital Improvements / Replacement Reserve – Typically, the useful life of a dam is considered to be 50-years. During that time frame the reservoirs fill with silt and require dredging, concrete inlet and outlet structures have begun to spall and require replacement or major renovation, stone rip rap requires replacement and the earth structure needs replacement of fill, re-vegetation and many times new toe drains, relief wells or other means to mitigate wet spots downstream of the structure.
Therefore, based on a 50-year useful life, 2% of the future cost of the structures should have been placed in a replacement fund each year as a reserve to replace elements of the structure as they age and become in need of major repairs or replacement. However, after 40-years of operation, no replacement reserve has been established. The 50-year future value of the original construction cost is $2,300,000. Based on expected NRCS participation in major capital improvements, the Subdistrict's 35% share of this would be $805,000. To establish this reserve amount would require $30,000 per year, with 3% accumulated interest, over the 20-year life of this Plan.
e. Engineering – This item includes the cost to establish and maintain the maintenance assessment along with engineering associated with the continued operation of the dams. Estimated cost is $12,000 per year.
f. Administration – The Administrative charge includes the apportioned cost of the HCD Secretary–Treasurer and the Administrative Assistant in the HCD office. It is estimated that 15% of the current Administrative costs of the Hocking Conservancy District are associated with the operations of the Margaret Creek Subdistrict. The current cost of these activities would be $21,700 per year. Over the 20 year life of this Plan at 3% inflation the average administrative cost would be $29,000 per year.
g. Board of Directors, Board of Appraisers and Conservancy Court – These are the projected costs associated with monthly meetings of the Board of Directors, and the annual meeting of the Board of Appraisers and Conservancy Court. Over the life of this Plan these are estimated to be $5,400 per year.
h. Legal Fees – Attorneys fees associated with preparing and filing the Appraisal Record and responding to any litigation associated with the readjustment and for future operation and maintenance activities. Spread over the 20-year life of this Plan, the annual cost would be $4,000 per year.
i. State Dam Safety Permit Fee – The State of Ohio requires a permit fee for all dams under their jurisdiction. The Ohio DNR inspects the four dams of the MCCD on a five-year cycle. This permit fee reflects the cost of those inspections and follow-up for items identified as requiring mitigation as a result of the inspection. The current $2,000 per year fee would average $2,700 per year over the life of this Plan.
j. Insurance – The Subdistrict must pay Liability Insurance associated with the ownership of the dams along with insurance for the personnel operating and maintaining the structures. This amounts to $9,800 per year over the 20-year Plan.
In summary, the cost to continue operation, maintenance, and replacement of the works and improvements of the Margaret Creek Subdistrict is estimated to average $167,000 per year, based on the 20-year Project Plan.
DAM SAFETY UPGRADES
$750,000 at 4% for 20-years
OPERATION & MAINTENANCE
Average Annual Cost over 20-years
Equipment Replacement Cost to HCD
2% of Construction Costs / Year
15% of HCD Administrative Costs
BOARD, APPRAISERS & COURT
Directors, Appraisers & Court Costs
STATE DAM SAFETY PERMIT
State Dam Inspection Permit Fee
5. Board of Appraisers ( ORC 6101.27)
At the time of making its order organizing a conservancy district or at any suitable time thereafter, the court shall appoint three appraisers to constitute the board of appraisers of the conservancy district, who shall in every case where appraisers are appointed under this chapter, be recommended by the board of directors of the conservancy district. The board of appraisers shall appraise the lands or other property within and outside the district to be acquired for rights of way, reservoirs, and other works of the district, and shall appraise all benefits and damages accruing to all lands within or outside the district and all benefits accruing to public corporations as entities by reason of the execution of the official plan.
6. Assessment Methodology
The Board of Appraisers (BOA) of the Margaret Creek Subdistrict reviewed a number of alternative methods to distribute the proposed assessment against benefited properties in the Subdistrict. The BOA propose that all properties within the Margaret Creek Watershed and within the boundaries of the Margaret Creek Subdistrict should pay an assessment based upon an estimate of the properties contribution of runoff to Margaret Creek. Ohio Revised Code (ORC) Section 6101.53 states that:
To maintain, operate, and preserve the…works…of the conservancy district, the board of directors of the district may, upon the substantial completion of the improvements and on or before the first day of September in each year thereafter, levy an assessment upon each tract or parcel of land and upon each public corporation within the district subject to assessments under this chapter, to be known as a conservancy maintenance assessment. (Emphasis added).
This was also based upon an Ohio Supreme Court decision in Miami County v City of Dayton which states that:
"The Court in the establishment of the district might well conclude that in the ordinary and natural course of events an acre of land within the watershed but 20 miles from the improvement would probably cast as big a burden of rainfall as an acre of land immediately adjoining the improvement, and that taking care of this surplus water, acre for acre throughout the district would be substantially equal benefit to the real property of that district."
The BOA has determined that an assessment will be levied based upon two components to estimate the contribution of runoff from each parcel. The first being the impervious area which includes all buildings, parking lots, paved driveways, sidewalks and any other hard surfaces. These were determined by measuring a statistical sample of single-family residential properties in the watershed, which produced an average residential impervious area of 3,800 square feet. This becomes one ERU (Equivalent Residential Unit). All single-family residential units would then be assessed one ERU. The impervious area for each Commercial, Industrial and Public parcel was measured and the impervious area divided by 3,800 sq. ft. to determine the number of ERU for each parcel. It is estimated that the ERU component of the assessment will be $22.75 per year / ERU. The second component of the assessment is the remaining non-impervious area for each parcel. Based on a Purdue University study the runoff from a 4-inch rainfall from typical grassland is about 0.8-inches, or 20%. The same study suggests that the impervious area of the parcel produces about 3.9-inches of runoff, or 97.5%. Therefore 20% of the total maintenance cost was distributed to the non-impervious area of all the parcels. This produced a projected rate of $0.86 per acre for the non-impervious area of each parcel.
7. Average Assessment by Land Use Classification
The following table provides the total number of parcels within each major land use classification and the projected average annual assessment for each class:
Number of Parcels
Total All Parcels
The Present Value of local cost with maintenance is $21,685,124. The estimated total benefits are $71,852,803 for a Benefit Cost Ratio of 3.31 to 1.00, as summarized below:
Reduced Flooding of Structures
Reduced Flooding of Agriculture
Reduced Flooding of Transportation
Water Storage for Supply
Reduced Soil Erosion
Construction of Project Facilities
To finance the required dam safety improvements, and provide funds for the continued operation, maintenance and replacement of the Margaret Creek Subdistrict will require an on-going maintenance assessment of $167,000 per year for the next 20-years. To accomplish this, 5,595 properties within the Margaret Creek Watershed will be assessed at a rate of $22.75 per ERU + $0.86 per acre per year. The total benefit of the Subdistrict's dams is estimated to be $71,852,803, with a Benefit / Cost Ratio of 3.31:1. It is anticipated that the assessment will be levied in September 2013 for collection beginning in January 2014.