SIPPO LAKE DREDGING PROJECT

PROJECT COMPLETION REPORT

Prepared by:

ms consultants, inc.

engineers, architects, and planners

Canton, Ohio

Prepared for:

The Stark County Park District

Canton, Ohio

February 1999

TABLE OF CONTENTS

Introduction

Background of Project

Bidding Process

Site Preparation and Plant Assembly

Year One Operation (1997)

Year Two Operation (1998)

Final Cost Summary

Project Summary and Evaluation

Attachments

Figures

Site Photographs

List of Reports

Key Personnel Involved in Sippo Lake Dredging Project

SIPPO LAKE DREDGING PROJECT

PROJECT COMPLETION REPORT

Introduction

Sippo Lake is a 107 acre lake located in Perry Township, Stark County, Ohio (see Figure 1). The lake was constructed in the late 1800s. The lake is impounded by a 445 foot earthen dam with a concrete outlet structure designed to maintain a constant water pool. Sippo Lake and a portion of the land surrounding the lake are owned and operated by the Stark County Park District. Primary water-based recreation uses are boating (small boats) and fishing, both from boats and from a fishing dock. Swimming is not permitted.

The lake has a large watershed area of 2,789 acres. The intense development of this watershed area has contributed to sediment flow to Sippo Lake. Through the years, the depths of the lake have decreased dramatically. Based on historic data and recent sediment measurements, there appeared to be an average of six feet of pre-1900 organic sediments over the till lake bottom. Above these pre-1900 deposits, there was roughly eight feet of semi-suspended organic sediments covered with an average of about five feet of relatively clear water. The pre-dredging bathymetry of Sippo Lake, as measured in 1995, is shown in Figure 2. The mean depth of the lake was about 5.1 feet, with a maximum depth of 14 feet in a small hole near the southern end of the lake.

The shallowness of Sippo Lake has been recognized as an impediment to the recreational use of the lake. In some years, explosive growth of large macrophytes has covered virtually the entire surface of the lake and adversely affected boating use. By the late 1980s, lake users were becoming increasingly concerned that the infilling of the lake would eventually make it unusable for recreation. Since Sippo Lake is one of Stark County’s most important recreation facilities, the loss of the lake would be a major loss for recreation in the Canton area.

Background of Project

The need to dredge Sippo Lake had been recognized for many years. In 1990, the Stark County Park District received a grant from U.S. EPA Clean Lakes Program to prepare a Phase I Diagnostic Feasibility Study for the lake. This study was prepared through a cooperative effort involving the Park District, the Ohio EPA, and the Northeast Ohio Four County Organization (NEFCO).

One key element of the study was the formation of a Technical Advisory Committee for Sippo Lake Restoration. The Advisory Committee involved a diverse group of people, including representatives from key governmental agencies, (OEPA, ODNR, and the Army Corps of Engineers), local academic institutions (Kent State University Biological Sciences Department), and local citizens. After extensive study and discussion, the Advisory Committee established a list of key actions that should be undertaken to restore Sippo Lake. One of the key actions identified by the Committee was the selective dredging of the lake. At the time of the original report in 1992, the cost of the dredging program (200,000 cubic yards) was estimated at approximately $1.1 million. Details regarding the Phase I study and recommendations are detailed in the report Sippo Lake Phase I Diagnostic-Feasibility Study (September 1992).

As a result of the Phase I study, the Park District secured lake restoration funding from the U.S. EPA (314 and 319 programs) and from the State of Ohio. Following the completion of the Phase I report, the Park District hired a consultant to develop detailed plans for various elements of the restoration program, including the dredging. Through 1993 and 1994, Fugro East worked on the various lake restoration elements. Through these efforts, a number of tasks were completed, including purchase of a macrophyte harvester and installation of fiber roll materials to serve as biological sediment barriers near the inflows of several tributary streams.

During this period, plans were developed for lake dredging. These plans were based on using a standard “dredge and dispose” methodology requiring large and deep containment basins. However, as work proceeded, two crucial problems became apparent. With sampling of the lake bottom material, it was found that the material had extremely poor settling characteristics, so the settling area for the dredging material would require an extremely long retention time. Second, it was found that the soil characteristics in the site for the settling pond were very unfavorable. Construction of the high dikes for a traditional settling area would require expensive site preparation and use of geotextiles for stability. The details regarding the original settling basin design were presented in a report titled Dredged Material Containment Area Preliminary Design Report (September 1994).

Planning for the containment basin proceeded to the point of advertising bids for construction of the settling basin in the fall of 1995. However, at this point, the Park District made the determination that the cost of constructing the containment basin (over $800,000) was excessive and would make it impossible to complete the dredging project with available funds. Additionally, the estimated time to complete the project (3 dredging seasons) was not considered acceptable.

The Park District then decided to investigate if any alternative technologies exist that could reduce the cost of lake dredging. Working with ms consultants, inc., initial contacts were made with the aggregate industry (sands and gravels) since this industry uses dredges and mechanical dewatering measures. While mechanical dewatering is possible in a lake dredging application, it was determined that the costs of the required equipment alone (probably near $2 million) and the labor requirements for plant operation makes this option infeasible.

Investigations were also made regarding the potential to adapt technologies used to dewater hazardous waste materials. This technology had been used on small dredging projects (golf course ponds, etc.) in the western United States. Companies were providing this service on a “turnkey” basis. However, quoted costs approaching or exceeding $10 per cubic yard were still to high to be feasible for Sippo Lake.

In late 1995, ms learned of lake restoration work being done in Florida by BCI (Bromwell & Carrier Inc.). Research publications indicated that BCI was working on lake projects with sediment characteristics similar to the highly organic materials found at Sippo and had developed an advanced sediment dewatering process that could be applicable for these materials. In late 1995, ms contacted BCI to determine if the new technology might be suitable for this project. After some discussion, ms and BCI developed an initial feasibility study (Sippo Lake - Initial Feasibility of Rapid Sediment Dewatering, March 1996). This study evaluated the feasibility of the BCI process for Sippo Lake. In the early 1990s, the Florida Institute of Phosphate Research (FIPR) patented a rapid dewatering process for fine-grained materials. This process utilized both polymer flocculation and a mechanical dewatering device. While initially developed for dewatering phosphatic clays, research suggested that the process may also work on fine-grained lake sediments. At this time, the process had never actually been tried on a full-scale project. Initial lab testing of the Sippo Lake sediments indicated that the material would flocculate well and dewater rapidly with this process.

One key theoretical advantage of this dewatering process was the cost savings associated with the preparation of the drying area. The process did not involve construction of the deep settling ponds. Instead, only low berms (about 5 to 6 feet) were to be build to confined the pumped dewatered material. Since the material would already be partially dewatered and would flocculate quickly, the high walls and long detention times associated with conventional dredging would be avoided.

Based on the initial tests, an initial project design was formulated with the following key elements:

1. Hydraulic dredging would be conducted at a rate of 2,500 cubic yards/day for 120 days. Dredge pumping rate would be approximately 2,000 gpm.

2. Dredged sediment, at approximately 5 percent solids, would be pumped to the dewatering plant located on the northwest side of the lake.

3. Dredged sediment would be flocculated and screened producing a thickened sediment at approximately 15 percent solids. Clean water resulting from the dewatering process would be returned to the lake.

4. Thickened sediment would be sequentially pumped to low-walled drying areas at a rate of approximately 1,500 cubic yards per day.

5. Sediment would be allowed to air dry and then “worked” (turned over) to enhance drying.

Following the initial feasibility study, the Park District directed ms and BCI to prepare an actual plan for the dredging project. The results are documented in the report Sippo Lake Sediment Removal Study: Sediment Removal and Disposal Plan (August 1996). This report provided detailed analyses of sediment characteristics and discussed various design alternatives. The report recommended a particular polymer material (Percol 455) and indicated that the estimated cost of dredging approximately 300,000 cubic yards of material would be $1,305,000, exclusive of planning and design costs. These costs were more fully detailed in Table 1.

TABLE 1

PRELIMINARY COST ESTIMATES - AUGUST 1996

(exclusive of planning and engineering costs)

Major Cost Components	Cost Estimate
Berm Construction	$50,000
Hydraulic Dredging	$600,000
Dewatering Plant Operations	$478,000
Drying Operations	$50,000
Site Reclamation, Wetland Mitigation	$125,000
Total Estimated Cost	$1,305,000

In late 1996, the Park District directed ms and BCI to prepare detailed construction plans for the various work elements included in the dredging project, including the design and assembly of the sediment dewatering plant and the construction of the sediment disposal area. These plans were essentially completed in early 1997. Figure 2 shows the original plan for the drying beds. Figure 3 shows the original plan for the sediment dewatering plant.

Also, in early 1997, the permit process was completed. The various permits associated with the project included:

401 Permit - The OEPA issued the original water quality certification on this project on June 19, 1995. This original certification was for a conventional dredging process.

404 Permit - The Corps of Engineers originally issued a 404 permit for conventional dredging on July 13, 1995. On October 31, 1996, the COE approved a “minor modification” of the original permit to allow the use of the sediment dewatering process, and also modified the wetland mitigation concept. The Corps of Engineers advised the Park District that the approval of this minor modification covered both the 401 and the 404 permit. The 404/401 permits also required wetland mitigation steps, with a mitigation completion date of December 31, 2000.

NPDES Permit - On January 23, 1997, the Ohio EPA indicated that a NPDES permit would not be required for the dewatering plant.

Stormwater Prevention Plan - On May 21, 1997, OEPA approved the Stormwater Prevention Plan (SWP3) for the sediment drying area.

Permit to Install (PTI) - On June 9, 1997, Ohio EPA issued a “Permit to Install” covering the sediment dewatering plant.

Bidding Process

Bids for the project were advertised in January 1997. A variety of separate bids were required for dredging, equipment acquisition, drying bed preparation, and dewatering plant assembly. The key bids that were awarded are listed in Table 2.

TABLE 2

SIPPO LAKE DREDGING - BIDS AWARDED IN 1997

Item	Low Bidder	Bid Amount	Comments
Dredging	Midwest Dredge Floyds Knobs, IN	$441,125	Included mobilization; basic dredging cost of $1.36 per cubic yard; 300,000 CY of hydraulic dredging.
Pumps	Midwest Dredge Floyds Knobs, IN	$66,521	Covers rental of feed pumps and thickened solids pump for a six month period.
Rotary Screen	Vulcan Industries Inc. Missouri Valley, IA	$76,000	The rotary screen is a major part of the sediment dewatering plant.
Clearing and Grubbing	Clearcut Land Service Inc. North Canton, OH	$38,480	Included removal of vegetation necessary to allow construction of drying areas.
Site Grading	Oakes Land & Excavating Massillon, OH	$111,668	Original construction of berms for drying areas.
Plant Assembly	Standard Plumbing & Heating Canton, OH	$98,430	Included providing a variety of piping, valves and other equipment needed for the plant; and the assembly of the plant.
Bulldozer Rental	Mahnen Equipment Company	$10,200	Rental of low ground pressure dozer for 6 months.
Flocculent	Allied Colloids Inc. Suffolk, VA	$96,000	Cost of $1.50 per pound for 64,000 pounds.
Flocculent Feed System	Allied Colloids Inc. Suffolk, VA	$12,000 ($2,000/mo.)	Covers rental for 6 month period.

Year One Operation (1997)

Many operational problems were faced during 1997. Because of these problems, it was not possible to complete the dredging in one season as originally planned. The major problems faced in 1997 are summarized below:

Late Start-up - The original bid opening for plant assembly was March 25. This would have allowed the District to build the plant in April and be pumping in May. However, because of the unfamiliarity of the project, all the potential assembly bidders withdrew, so the District had to re-bid, delaying assembly until May and start-up until June 15, 1997. This delayed the project approximately 30-40 days. The importance of this delay became increasingly apparent later in the year.

Problems with Polymer Delivery System - By the beginning of June, the plant was ready for operations. The first two weeks of June were utilized for a shakedown and testing period, with actual operations starting on June 15. Within the first few weeks of operation, it became apparent that there was a substantial problem with the polymer delivery system. The polymer delivery system was designed to allow continual plant operation. However, in reality, the polymer system was unable to produce material as fast as needed. While the plant could produce about 20 gallons per minute (gpm) of polymer material, the operation typically consumed about 28 to 30 gpm. This higher rate was needed to provide adequate flocculation of material. Since polymer was consumed faster than it could be produced, this made it necessary to operate the system in an “on-off” manner. The dredger and plant would run until the polymer was depleted, then both would be forced to wait until more polymer material was mixed. In June 1997, the plant typically operated only 3.5 to 5 hours per day. This continued until the plant was modified with additional polymer storage tanks in mid-August. This modification allowed the operators to mix polymer during the night, providing a larger supply of material in the morning. With this change, after August 16, the plant was able to operate about 7 hours per day, allowing much higher production.

The actual polymer usage rates in the field were considerably higher than the rates predicted by laboratory analyses and appeared to be due to the nature of the dredged sediments. This may be a typical situation in sediment dewatering. Also, in practice, material was sent to the drying beds at a lower solids percentage than was predicted by laboratory analyses.

Rotary Screen Problems - Until field modifications were made, mechanical breakdowns of the rotary screen were a major difficulty. Multiple weld and bolt breaks were experienced. Repair of the weld and bolt problems delayed the project about 5-6 days.

Drying Bed Management Problems - As a result of this project, we have learned that the management of the drying beds is a more intensive operation than originally anticipated. This is particularly true because material was sent to the beds at the lower solids percentage than originally anticipated. For bed management, it is necessary to have at least one bulldozer in operation at all times. Further, the size of the original bulldozer that was leased was inadequate. This was further complicated by the poor mechanical condition of the original unit. The ongoing breakdowns of this unit caused some project delays, affecting the project by at least 3-5 days.

To some degree, bed management problems may be an unavoidable aspect of utilizing this system of sediment dewatering in a northern climate with limited bed capacity. If the polymer feed capacity had allowed processing the material at a higher rate in the early part of the season, it is likely that the beds would have been filled to a point that operations would have stopped to allow drying. Given the late start date, it is very possible that two dredging seasons were necessary, even without the polymer feed problems.

The late start date caused another problem associated with Ohio climate. As work proceeded, it became apparent that dredging would not be completed by the original October completion date. A decision was made to continue dredging as long as possible, through November and possibly into December. However, in October, it became apparent that the change in weather (shorter daylight, cooler nights) had a dramatic effect on the dewatering characteristics of the sediments. In mid-October, the drying of the material essentially stopped, making it impossible to continue dredging due to the lack of drying bed space.

Sediment Qualities - The nature of the lake sediments proved to be more variable than anticipated, and the different materials react very differently with the polymer. In some areas, this required the dredger to utilize the “undercut” dredging technique that provided a material that was more conducive to flocculation. This procedure is much slower than normal dredging. At the extreme northern end of the lake, the very fine material encountered reacted poorly with the flocculent, requiring slow dredging rates. This also delayed the project. In a few areas, the dredging plan was revised to avoid areas that were known to contain material that would react poorly with the flocculent.

The actual dredging period for 1997 extended from June 15 through October 14, a total of 120 days. During this time, the dewatering plant operated a total of 579 hours over 104 working days. This averages 5.5 hours of plant operation per day. Daily operation hours increased in August, when 2 extra polymer storage tanks were installed.

Based on in-lake measurements, about 152,700 cubic yards of material were dredged in 1997, or about 264 cubic yards per hour of plant operation. This was approximately 50% of the total dredging project.

Year Two Operation (1998)

Plant and dredging operations were much smoother in 1998. Before work was started, most of the dewatered material already in the drying beds was removed by pushing material to the sides of the beds. The beds were then regraded and reconfigured to allow more efficient bed management. Also, two additional polymer storage tanks were added before the start of 1998 operations. This further increased the operators’ ability to make and store mixed polymer materials overnight. By having large quantities of polymer available, the dredgers were able to operate on a much more continuous and efficient schedule. In 1997, the plant only operated about 5.5 hours per day out of a 10 to 12 hour working day, meaning the plant was in operation less than 50% of the time. In 1998, the working day was shortened to 8 hours, but the plant was able to operate 6.3 hours a day, or about 75% of the time. Since some downtime is inherent in the process (dredge equipment downtime, plant maintenance, drying bed problems) the 75% operation may be about as good as can be accomplished.

Plant and dredging working schedules were also adjusted. In 1997, the basic attempted working schedule was 10 to 12 hours per day, 7 days per week. In 1998, the basic schedule was 8 hours per day, 6 days a week. The scheduled off day each week allowed plant maintenance, and also provided a better balance between plant operation and material drying in the beds.

For 1998, the dredging period ran from May 4 to September 20, a total of 110 calender days. During the last month of the operation, a major change was made in plant operations. The rotary screen was bypassed, and material was treated and pumped directly to the beds without the screening process. While some extra water was sent to the beds, it appeared that the flocculated material reached the beds in better condition and settled faster than it had when it passed through the rotary screen. The water separated quickly from the material in the beds. The results of this experiment suggest that the extra disruption of the forming flocculents that occurs through the screen and the thickened solids pump may actually result in retarding the settling of the treated sediment.

Also, in the last weeks of the project, a mechanical dredge was brought in to clean out the in-lake settling areas that were created with bioengineering fiber rolls at the stream outlets. This work was not part of the original dredging plan. The mechanical dredge was also used to remove material near the northwest corner of the lake that could not be hydraulically dredged due to the presence of extensive debris, including logs and trash.

In 1998, the plant operated 84 days out of a dredging period of 110 days. The plant operated a total of 527 hours, or about 6.3 hours per working day. A total of 150,600 yards of material was dredged in 1998, or about 286 yards per hour of plant operation.

Table 3 provides an overall chronology of the Sippo Lake dredging program, beginning with the initial planning and continuing through the dredging process.

TABLE 3

CHRONOLOGY OF EVENTS - SIPPO LAKE DREDGING PROJECT

Year	Month	Event
1988	December 29	First meeting of Sippo Lake Citizens’ Advisory Board
1989	December	Report on bathymetric survey by Crossroads RC&D
1990	February 6	Sippo Lake Technical Advisory Committee holds first meeting, includes former Citizens’ Advisory Board.
1991	September 19	Alternative dredging plans presented to Advisory Committee.
1991	December 11	Dredging plans presented to public, including Lakeshore Homeowners Association.
1992	January 29	After several revisions, plan “F” is developed and presented to Advisory Committee.
1992	January	Application for “Phase II” funding prepared with Ohio EPA and submitted to USEPA.
1992	June	Original wetland delineation study prepared by Ohio EPA.
1992	September	Draft “Sippo Lake Diagnostic-Feasibility Study” published.
1992	October	USEPA approval of Section 319 and Section 314 grants.
1993	February	Final Diagnostic-Feasibility Study completed.
1993	September	Wetland delineation report by Fugro completed.
1994	September	“Dredged Material Containment Area Preliminary Design Report” completed by Fugro.
1994	October	Approval of COE 404 permit for dredging, fill of wetland areas.
1994	December	Ohio EPA approval of 401 Water Quality Certification, includes restoration of 3.6 acres of wetland on-site and 1.9 acres either on-site or off-site.
1995	September	Park District asks ms consultants to evaluated new dredging technologies, ms contacts considers various potential methods.
1995	December	ms identifies polymer flocculation technique being developed by BCI of Lakeland, Florida as the most promising procedure, Park District hires ms/BCI to evaluate feasibility.
1996	January	ms/BCI collects lake bottom samples for sediment analysis.
1996	March	“Initial Feasibility of Rapid Sediment Dewatering” report completed by ms/BCI, identifies polymer flocculation as the preferred technology.
1996	May	Approval of ODNR Natureworks grant.
1996	October	Modified dredging and wetland plan approved by Corps of Engineers, allows use of sediment dewatering.
1996	August	“Sippo Lake Sediment Removal Study: Sediment Removal and Disposal Plan” completed by ms/BCI.
1996	December	Bids out for lake dredging, awarded to Midwest Dredging.
1997	January	Bid out for rotary screen, awarded to Vulcan.
1997	March	Bids out for assembly of dewatering plant, no responsive bidders.
1997	April	Rebid for assembly of dewatering plant, awarded to Standard Plumbing.
1997	May	Dave Price hired as dewatering plant operator.
1997	May	Standard Plumbing completes assembly of dewatering plant.
1997	May	Plant equipment delivered to site.
1997	June	“Permit to Install” approved by Ohio EPA.
1997	June	“Shakedown” period for dredging/dewatering plant.
1997	June	Oakes completes grading of drying beds.
1997	June	First official dredging day, June 16.
1997	June	Bob Fonte & Bill Malson present paper on project at “Connecting Ohio Watersheds” conference.
1997	October	Dredging work halted due to lack of drying cell space and deteriorating weather conditions.
1998	May	Restart of dredging work.
1998	March	Bids for regrading of drying beds, awarded to Oakes.
1998	August	Hydraulic dredging completed.
1998	September	Mechanical dredging of marina area and baffle areas completed.

Final Cost Summary

The following table compares actual project costs to the original estimates in the BCI report of August 1996. This comparison is being done for planning purposes for future projects. The costs shown on the table are subject to change based on final site reclamation and management costs and credits for sale of salvage equipment items (rotary screen, etc.) that have not been finalized as of February 1999. These changes should be relatively minor. The purpose of this table is not to provide an exact accounting of project costs, but instead is intended just to provide a comparison of estimated costs versus actual costs. The table is consistent with the cost summary provided to the Park Board on September 1998.

The actual dredging construction and operation cost of $1,667,494 is about $364,000 (28%) higher than the original cost of $1,303,000. The extra cost is primarily a result of operating two years instead of one, and also the extra costs associated with cleaning and reshaping beds before the second year. This second year of dredging was forced because the plant could not process material as fast as originally hoped, and the sediment drying in the beds was slower than anticipated due to the higher percentage of water pumped to the drying areas.

TABLE 3

ORIGINAL PLANNING ESTIMATES COMPARED TO ACTUAL COSTS

MAJOR COST COMPONENT	1996 COST EST.	COST/ C.Y. (300,000)	FINAL COST	COST/C.Y. (303,354)	COMMENTS
Berm construction	$50,000	$0.17	$139,883	$0.46	Berm construction cost exceeded original estimate, possibly because of higher local construction costs and high costs associated with poor soil conditions. Approximately 20 acres of drying beds were graded.
Hydraulic dredging	$600,000	$2.00	$582,067	$1.92	Even with extensive “downtime” costs in 1997, dredging cost is still close to original estimate. Does not include mechanical dredging. Total of 303,000 CY of material dredged.
Dewatering plant and cell operations	$528,000	$1.76	$820,544	$2.70	Higher costs were due to two years of operation, rather than one. Includes costs involved with regrading drying beds prior to second dredging season. Includes plant assembly, polymer, payroll.
Site reclamation	$125,000	$0.42	$125,000	$0.42	Some reclamation has already been accomplished under operations work. Reclamation cost will depend on ultimate decisions regarding site (for example, preparation for education building). Under the 404 permit requirements, mitigation must be complete by 12/31/00.
TOTAL HYDRAULIC DREDGING CONSTRUCTION AND OPERATIONS	$1,303,000	$4.34	$1,667,494	$5.50	Includes $125,000 for site reclamation, actual costs not determined. Does not include any income from salvage (sale of rotary screen).
Design/construction management	$202,129	$0.67	$202,129	$0.67	BCI estimate did not include design costs, design and management costs added in to BCI estimate to allow total comparison.
Mechanical dredging			$26,200		Approximately 2,000 c.y., not considered in original estimate.
TOTAL HYDRAULIC AND MECHANICAL DREDGING, INCLUDING DESIGN AND MECHANICAL DREDGING	$1,505,129	$5.02	$1,895,823	$6.25	Includes $125,000 for site reclamation, actual costs for reclamation not determined.

FINAL OPERATIONS SUMMARY

Table 5 compares the final operations results to the original estimates developed in 1996. The total cubic yards dredged met the original goal. The actual hours of plant operation was slightly less than the original estimate. However, these hours were distributed over many more days than originally estimated due to the extensive downtime experienced in 1997.

TABLE 4

FINAL OPERATIONS SUMMARY

PARAMETER	1997	1998	TOTAL	BCI ORIGINAL ESTIMATE	COMMENTS
Total cubic yards dredged	152,767	150,587	303,354	300,000	Estimates based on lake soundings. Does not include yardage dredged mechanically
Total hours plant operation	579	527	1,106	1,200	Original report anticipated 120 days @ 10 hours per day.
Total days plant operated	104	84	188	120	Original report anticipated 10 hours of plant operation per day. This was not possible due to the polymer delivery system problems.
Total duration of operation - days	120	110	230	180	Original report anticipated completion of dredging in 6 month dredging period. This could not be accomplished. However, even under best conditions, drying bed operations may have constrained ability to complete project in one season.
Hours operation per day	5.5	6.3	5.9	10.0	In 1997, plant operated 5.5 hrs./day in a 10 to 12 hour working day. In 1998, the plant operated 6.3 hours per day in an 8 hour working day. Achieving average of 6 hours out of an 8 hour day (75%) may be as good as possible.
Yards dredged per hour of plant operation	263.8	285.7	274.3	250.0	Possibly solids % in dredged material higher than expected, may account for higher number. If not constrained by plant, Midwest claims to be able to dredge 365 cy per hour.
Total pounds of polymer utilized	38,575	32,403	70,978	64,000	Some polymer lost in 1997 due to downtime, operations more efficient in 1998. Does not include polymer used for mechanical dredging in 1998.
Cost of polymer utilized	$57,863	$48,605	$106,467		Does not include polymer used for mechanical dredging in 1998.
Polymer cost per yard dredged	$0.38	$0.32	$0.35
Estimated wt. of dry solids (tons)	12,962	12,807	25,769		Estimate based on original lab tests of sediments, should be considered as rough estimate.
Estimated wt. of dry solids (million lbs.)	25.9	25.6	51.5
Polymer used per ton of dry solids	3.0	2.5	2.8	1.0 to 2.0	Higher usage rate necessary to achieve flocculation, meant that polymer system could not “keep up” until auxiliary tanks added in 1998. Operation more efficient in 1998.
Average percent solids of dredge output			5.2%	4.5%	Solids output of dredge higher than forecast.
Sediment removed by mechanical dredging		2,000 CY	2,000 CY		Not included in original dredging plan.

Project Summary and Evaluation

* The basic goal of removing 300,000 cubic yards of sediment material from Sippo Lake was met. Lake depths were substantially increased to the point where a large portion of the lake has a depth of 10 feet or more, and this should help control the spread of aquatic macrophytes over the total lake surface.

* The polymer sediment dewatering process was a viable solution to the problem faced at Sippo Lake. Based on observations of untreated material occasionally sent to the drying beds, it is likely that this material would have taken an exceptionally long time to settle and dewater without some kind of treatment. It is questionable if adequate settling could have been accomplished with a conventional drying bed system.

* The final project cost of $6.25 per cubic yard of material dredged is within the range of costs normally associated with dredging projects of this size.

* One of the major problems faced in dewatering plant operation was the inability of the polymer delivery system to provide adequate quantity of material. The actual rate of polymer usage required to flocculate the material was far higher than predicted in lab tests. Future projects should allow a large “margin of error” for polymer delivery, since the extra cost involved in a larger polymer system would be minimal in comparison to costs associated with project delays.

* Drying bed operations are labor intensive. For a project of this size, a full-time bulldozer operator is mandatory. The size of the machine required should also be carefully evaluated. Machines that are too small cannot keep up with the required material handling, but machines that are too large are too heavy to operate in the wet conditions that are present.

* The position of plant operator is a key position to fill. It is important that the operator have some familiarity with similar types of polymer systems, such as are commonly found in wastewater treatment facilities. The plant operator should also be able to make independent operational decisions without continual supervision. The extra money spent to hire a skilled operator will result in long-term savings to the project.

* In northern climates, the use of this type of polymer dewatering is essentially limited to the months from May through October.

* While the flocculation process works, the rotary screen system may not be the most appropriate method. During operation, it became increasingly clear that the flocculated material should be handled and disrupted as little as possible. The rotary screen and associated pump tended to disrupt the flocculation process.

Figures

Figure 1 Project Location Map

Figure 2 Lake Bathymetry Before Dredging

Figure 3 Plan for Drying Beds (Original)

Figure 4 Plan for Sediment Dewatering Plant (Original)

Figure 5 Sippo Lake Dredged Areas

SITE PHOTOGRAPHS

LIST OF REPORTS

The following reports were prepared as part of the Sippo Lake dredging project:

Fugro East Inc., 1994, Dredged Material Containment Area Preliminary Design Report, Prepared for the Stark County Park District.

Fugro-McClelland (Midwest) Inc. and ms consultants inc., 1993, Wetland Delineation Report, prepared for the Stark County Park District.

ms consultants, inc. and Bromwell & Carrier, Inc., 1996, Sippo Lake - Initial Feasibility of Rapid Sediment Dewatering, prepared for the Stark County Park District.

ms consultants, inc. and Bromwell & Carrier, Inc., 1996, Sippo Lake Sediment Removal Study: Sediment Removal and Disposal Plan; prepared for the Stark County Park District.

Northeast Ohio Four County Regional Planning and Development Organization, 1992, Sippo Lake Phase I Diagnostic - Feasibility Study.

KEY PERSONNEL INVOLVED IN SIPPO LAKE DREDGING PROJECT

The dredging of Sippo Lake was a complex project that required the close cooperation of many individuals. Because of the special problems that were faced, many persons acted “above and beyond the call of duty” in bringing about the successful completion of the project. Some of the key people that were involved in the project are listed below:

Stark County Park District

Robert Fonte, Park Director

Debbie Graf, Administrative Assistant

David Price, Head Dewatering Plant Operator

Tony Ulrich, Plant Operator (1997)

Gary McFarland, Plant Operator (1998)

David Copeland, Bulldozer Operator (1997)

George Cuckler, Maintenance Supervisor

ms consultants inc.

R. Richard Fawcett, P.E., Principal in Charge

William M. Malson, Project Manager

Bromwell & Carrier Inc.

Richard Powers, Principal

Larry Sauls

Midwest Dredge & Excavating

Eric Wells, President

Jerry Brucker, Project Superintendent

Dexter Cowan, Dredge Operator

Ben Marrs Jr., Laborer

James Wofford, Laborer

Raymond Givan, Operator

Brian Collins, Laborer

Oakes Land & Excavating

Ed Friedl, Manager

Standard Plumbing & Heating

Dan Haren, Manager

John Blandford, Superintendent

Allied Colloids Inc.

Don Luke

Preferred Temporary Services

Doug Hill