1

2

LAKE PANORAMA EROSION ASSESSMENT June 1, 2012

INTRODUCTION This report provides an assessment of erosion control as it pertains to Lake Panorama. It addresses silt accumulation, silt removal and silt prevention as of June 1, 2012, and is a factual assessment of condition and costs. BACKGROUND Lake Panorama Association (LPA) and Lake Panorama Rural Improvement Zone (LP RIZ) have three erosion control studies on file. These are Shive-Hattery (1982), Cochran and Wilken, Inc. (1998) and Shive-Hattery (2001). Although some components of these reports are dated, the general assessment of Lake Panorama’s watershed remains reliable for long-term planning purposes. Shive-Hattery completed a report in 1982 for Central Iowa Power Cooperative (CIPCO). At that time, CIPCO was planning to construct a fossil-fueled power plant south of Panora and intended to use the lake as a cooling water resource. The report estimated the Lake Panorama watershed, or drainage area, as being approximately 440 square miles, with 120 square miles of the watershed classified as highly erodible Kansas Glacial Till and 320 classified as Wisconsin Glacial Till Drift. Soil type was generally characterized as having “no appreciable clay content” and therefore being “friable and subject to erosion.” The report noted the Lake Panorama watershed was divided among three counties:

Carroll County - 64% Guthrie County - 20% Greene County - 16%

The 1982 study attempted to forecast silt accumulation using suspended sediment gauging stations. This report estimated annual accumulation of 533 acre-feet per year, which translates into approximately 860,000 cubic yards. (Subsequent studies and dredging records have shown this to be overstated.) The 1998 study by Cochran & Wilken, Inc. also examined the watershed and presented a similar assessment on watershed size and soil characteristics. This study stated Lake Panorama’s watershed consisted of approximately 433 square miles, or 277,120 acres of ground. This was determined to be primarily agricultural cropland, with small percentages of pasture, forest and urban land. This report explained the relatively high watershed area to lake surface area (221 to 1), combined with the high percentage of cropland and erodible soils, contributed to excessive sedimentation rates. Studies by Cochran and Wilken (1998) and Shive-Hattery (2001) reviewed silt accumulation in an attempt to establish an annual average. Both studies highlight the fact silt accumulation

3

varies significantly from year to year, which makes it difficult to establish an accurate average. The 1998 study estimated an average silt accumulation rate of 225 acre-feet per year, or 362,939 cubic yards. The 2001 study estimated an average silt accumulation rate of 250 acre-feet per year, or 403,250 cubic yards. Dredging records indicate these numbers to be more accurate than Shive-Hattery’s pre-dredging forecast of 533 acre-feet per year. CURRENT ASSESSMENT OF LAKE PANORAMA For this report, Lake Panorama is divided into three categories: The Middle Raccoon River, Burchfield Cove, and all other coves. Analysis of these three categories focus on the characteristics of each, including silt removal, silt storage and silt prevention. The Middle Raccoon River Lake Panorama is fed by the middle fork of the Raccoon River, which enters dredging territory at the Fansler Bridge, at 180th Trail. The Middle Raccoon River represents the vast majority of Lake Panorama’s total watershed and subsequently, its primary erosion control concern. Silt Removal Silt is removed from the Middle Raccoon River through the use of a dredge. This operation achieves a significant economy of scale compared to other operations and represents the most efficient removal process at Lake Panorama. Silt removal from the Middle Raccoon River is best analyzed by segregating the river into two segments — the Fansler Bridge Segment and the Upper Basin Segment. The Fansler Bridge Segment is the area beginning at the Fansler Bridge and extending downstream approximately 2,400 feet. The Fansler Bridge represents the furthest upstream point at which dredging has been completed. This area has been dredged twice to a depth of 11 feet using the now full CIPCO basin. This area once served as a settling area for incoming silt but is not currently effective for this purpose as significant deposits of sand and gravels have accumulated. Current hardware and storage options prevent dredging the Fansler Bridge Segment. An estimated 25 to 30 acres of islands have formed in this half-mile segment, with depths of 2 feet or less being common. LPA staff estimates 650,000 to 750,000 cubic yards of heavy material are deposited in the Fansler Bridge Segment. The conditions of the Fansler Bridge Segment are problematic as the shallow depths in this area cause silt to be deposited further downstream. Additionally, regular spraying is required to ensure willows don’t become established on the islands. Removal of significant vegetation was completed as part of the initial dredging to the Fansler Bridge and was a very expensive process.

4

Figure 1. Upper Lake Panorama showing the two major dredging areas and silt retention facilities in the area.

Figure 2. HORIZON dredging in the easterly end of the Fansler Bridge Segment. Picture taken in fall 2011.

5

Figure 3.The Fansler Bridge segment (A to B) is characterized by high sand and gravel content and is not completely reachable by current dredging.This photo was taken after the first complete dredging in 2006.

The Upper Basin Segment refers to the area beginning 2,400 feet downstream from the Fansler Bridge and extending downstream to the Upper Basin of Lake Panorama. This represents the current area of dredging operations on Lake Panorama. Original dredging of the upper basin achieved an average depth of 10 feet. Maximum depth in this segment is currently 9 feet with some areas being as shallow as 6 feet. LPA’s current dredging practice is to excavate to the original bottom. This averages a finished depth of 13 feet, with maximum depth of 17 feet. The amount of silt accumulated in the upper basin is a very dynamic number as several hundred thousand cubic yards are washed in and dredged out annually. LPA staff estimates 400,000 to 600,000 cubic yards of silt are deposited in the upper basin and adjacent river channel.

Figure 4. Upper Basin dredging is the focus of the dredging program.

6

The lack of settling area in the Fansler Bridge segment results in increased rate of silt accumulation in the Upper Basin. Lake Panorama has been able to effectively contain silt to the Upper Basin segment, but it should be noted the level of protection from significant silt events would be maximized if both the Fansler Bridge segment and the Upper Basin segment were kept open on an ongoing basis. Silt removal and storage in the Upper Basin Segment is extremely cost effective, compared to other areas of the lake. Current cost of operations is estimated to average $2.50 per cubic yard. (This average is based upon $1.65 per cubic yard for fuel and labor, $.35 per cubic yard for storage and $.50 per cubic yard for equipment maintenance and depreciation. It is important to note there are many factors in play that could cause Lake Panorama to incur significantly higher cost per cubic yard in the future.) Maintaining good depth in the Upper Basin also is a key factor to ensure LPA can effectively contain debris such as trees, logs and cornstalks. Maximizing the cross sectional area of the lake in this area slows water, reduces pressure against the boom and allows for a higher percentage of debris to be retained. This does not factor into silt removal, but is a related water quality endeavor, which is necessary to protect the viability of Lake Panorama. Silt Storage The Original CIPCO Basin was constructed in 1984 and served as silt storage for Middle Raccoon River dredging until the late 1990s. The construction plans for this basin estimate the storage capacity as being 8.5 million cubic yards. The 1998 study by Cochran and Wilken reviewed the status of silt storage and noted the 8.5 million cubic yard CIPCO basin had been fully exhausted. Cochran and Wilken discussed the addition of approximately 3.5 million cubic yards of silt storage to serve the Middle Raccoon dredging effort. The report noted this additional storage could be achieved through the recently constructed Gibson Basin and the two-phase expansion of the CIPCO Basin. The Gibson Basin was designed to hold 1,144,496 cubic yards and was first utilized in July 1999. The Gibson Basin is considered full and is no longer suitable to contain dredging spoils. It serves only as a retention structure for a minor cove near the Upper Basin. The CIPCO expansion was completed in two phases, with phase one finished in June 2001. This added eight feet to the dam and resulted in an additional 958,318 cubic yards of storage. Phase Two, completed in June 2002, added a second eight-foot lift to the dam. This resulted in another 1,382,624 cubic yards of additional storage. As of December 2004, the additional storage provided by the two-phase CIPCO Basin expansion was exhausted. Further expansion of the CIPCO Basin has not been explored as dredging is currently served by the County Basin. Preliminary conversations indicate expansion of the CIPCO Basin would not be feasible from an engineering or permitting standpoint. An in-depth engineering study would be required to confirm this. Since 2006, all Middle Raccoon River silt has been pumped to the County Basin. The County Basin has an estimated capacity of 10 million cubic yards and is roughly 20% full. The most notable advantage to the County Basin is its size and cost. Average deposits of

7

300,000 cubic yards per year result in a more than 30-year life-span for the structure, which addresses Middle Raccoon silt storage until nearly the year 2040. Cost of the basin was approximately $3.5 million, which results in a $.35 per cubic yard storage expense. While the County Basin’s size is generally an advantage, it also poses some challenges. Pumping into a basin of this size requires LPA to transfer spoils approximately 8,700 feet. Additionally, the elevation of the dam in relation to the lake creates approximately 90 feet of head pressure for the dredge. The extreme distance and head pressure prevent dredging of the Fansler Bridge Segment with current equipment. Dredging is effective in the Upper Basin Segment, although booster pumps will likely be required to utilize the far end of the basin. Property rights for the County Basin are a long-term concern, as only a portion of the property is owned by the Lake Panorama Association or Lake Panorama RIZ. Flood easements essential to basin usage are in place with five private property owners. The first of these easements expires on September 25, 2029, with the others following shortly thereafter. LPA currently estimates 7 million of the 10 million cubic yard capacity will be utilized by 2029. This would result in approximately 3 million cubic yards being unused at the expiration of the flood easements. It is possible this number could exceed 3 million cubic yards of available storage if de-watering is successful in significantly consolidating the stored silt. Extension of flood easements will be at the discretion of the landowners and could represent a significant expense to LPA. No engineering studies have been pursued to address silt storage after the County Basin is exhausted. It should be noted maintenance of the County Basin dam will represent an ongoing liability for LPA as structural integrity must be maintained indefinitely. Expenses for this are infrequent but have the potential to be significant.

Figure 5. View of County Basin settling area from outlet structure when filling for the first time.

Silt Prevention As noted in the engineering studies, the scope of the Middle Raccoon watershed is massive and prone to erosion. The 1982 Shive-Hattery report states, “…it is imperative that a long range watershed plan be designed to reduce sediment flow to Lake Panorama.” Although no engineering studies have recently been completed, it would appear the watershed condition is very similar to what concerned Shive-Hattery and CIPCO three decades ago. LPA and Lake Panorama RIZ attempted to increase erosion prevention in the late 1990s by supplementing and encouraging enrollment in conservation programs. Effectiveness of this effort was difficult to evaluate due to the scope of the watershed and the inconsistent nature of

8

silt accumulation. Additionally, the strategy’s dependence on government incentives caused its success to wane with government funding. LPA and Lake Panorama RIZ have been represented in Raccoon River Watershed work groups and are participating in the preliminary phase of establishing a 28E organization to improve water quality and mitigate flood risk in the South and Middle Raccoon River. Efforts of this nature progress slowly, due to the number of parties involved and competing politics. However, LPA and Lake Panorama RIZ recognize cooperative efforts are the most likely method by which large-scale watershed improvement will be achieved.

Middle Raccoon Summary LPA and Lake Panorama RIZ have developed an extremely cost-efficient operation for removing and storing silt deposited in the Middle Raccoon River area of the lake. Operations are expected to remain unchanged through 2029, when the first of the County Basin easements expires. This date could extend to 2040 if negotiations are successful. Although the same model will be followed, operational costs can be expected to increase. Most notable among expenses is annual diesel fuel consumption for dredge operations. Diesel fuel burned in 2010 and 2011 was 39,012 gallons and 37,310 gallons respectively. Booster pumps required to reach the far ends of the basin will increase the total amount of fuel required. Short-term volatility in fuel prices is managed via fuel contracts. However, the long-term volatility of fuel prices is beyond control. The solution to silt storage beyond 2040 poses one of Lake Panorama’s most significant, long-term planning priorities. Short-term improvement in silt prevention is extremely unlikely for the Middle Raccoon River area of Lake Panorama due to the size, soil types and agricultural practices of the watershed. LPA and Lake Panorama RIZ are committed to advocating long-term improvements in silt prevention but recognize this must be done as part of larger efforts that establish cooperative relationships with local government entities and agriculture. ____________________

9

____________________ Burchfield Cove

Figure 6. Dredging upper end of Burchfield Cove

Figure 7. Watershed map of Burchfield Cove covers about 10 square miles.

Burchfield Cove is the second largest tributary to Lake Panorama. Its size of 6,406 acres makes it a very distant second to the Middle Raccoon River and represents only 2.3% of the

10

total watershed. Although it is much smaller than the Middle Raccoon River, it still represents a significant and expensive concern for Lake Panorama. Storage alone bears a cost of eight to ten times that achievable at the County Basin. The majority of Burchfield Cove is large enough to accommodate Lake Panorama’s dredge, which allows for large-scale silt removal. However, the cost for dredge operations and silt storage is exponentially more expensive than what can be achieved in the Middle Raccoon River. Supplementary silt removal has been completed with a long-stick excavator and clamshell barge in areas that are too narrow for effective dredging. This allows full access to the cove but is much less efficient than dredging. Silt Removal LPA completed comprehensive dredging of Burchfield Cove in 2005, which established depths of 8-10 feet. Silt removed was approximately 123,000 cubic yards. LPA returned in 2008 to complete “maintenance” dredging in the amount of 13,804 cubic yards. This involved only the Burchfield creek channel and the west fork. Heavy spring rains in 2009 negated this progress and caused LPA to return in 2009 for another 18,770 cubic yards of “maintenance” dredging. At the time of this report, Burchfield Cove is in need of comprehensive dredging in the estimated amount of 125,000 to 150,000 cubic yards. Silt Storage Burchfield Cove was served by the Cornfield Court silt basin from 1994 through 2009. This structure was constructed to hold 185,000 cubic yards of spoils and is currently exhausted. (Total yards stored in Cornfield Court are estimated to exceed 200,000 as the heavy nature of the spoils have allowed for stockpiling in the immediate discharge area.) Lake Panorama RIZ is in the process of designing and permitting the approximately 350,000 cubic yard Scott basin to serve Burchfield Cove. Cost of the basin is estimated to be near $3.00 per cubic yard, or slightly more than $1,000,000. Construction is expected during the summer and fall of 2012. Comprehensive dredging of Burchfield Cove will follow in either fall 2012 or spring 2013.

11

Figure 8. The Scott Basin location should serve the Burchfield Cove area for over twenty years.

The Scott Basin will be constructed on leased property and will be contractually available for use through 2047. The irregular nature of Burchfield Cove siltation makes it difficult to estimate the practical life of this basin beyond classifying it as having at least 20 years of storage capacity. Increased conservation practices in the watershed could extend the life of this structure nearer to 2047. Storage beyond 2047 has not been seriously analyzed. Likely options would be the construction of a third basin or the excavation and reuse of the Cornfield Court Basin. Excavation and reuse of the Cornfield Court Basin was estimated by Shive-Hattery in 2011 as part of the Scott Basin feasibility study. Costs were estimated to be between $6 and $8 per cubic yard, assuming the spoils could be given away. (This is not necessarily a valid assumption but was not pursued as the cost difference made it a moot point.) 2011 comparisons would indicate the construction of a third basin would be roughly half the price of excavating and reusing the Cornfield Court Basin.

12

Figure 9. Dredging the west fork of Burchfield Cove. Hydraulic dredging is much more efficient than mechanical dredging when it’s possible.

Silt Prevention Iowa DNR and LPA completed a preliminary assessment of Burchfield Cove and attempted to classify the amount of silt received from streambank erosion versus sheet and rill erosion. This analysis suggests nearly two-thirds of Burchfield Cove’s silt originates from streambank erosion. Burchfield Cove represents a good opportunity for LPA and Lake Panorama RIZ to undertake an aggressive erosion prevention program. The watershed is small enough to be manageable yet large enough to make a difference. Additionally, Lake Panorama should benefit because landowners and tenants are local neighbors with whom personal relationships already exist. A goal of a Burchfield Cove preventative campaign would be to serve as a model project for other watershed improvements. It is essential Lake Panorama successfully document the “before and after” effects of any project in Burchfield so information can be used as a basis for future grant applications. Projects in the rest of the watershed are much more likely to be funded if Lake Panorama can prove it successfully partnered with landowners and producers to improve the watershed and reduce sediment. Nitrate removal also should be monitored as that could open the door to other funding streams.

13

Summary of Burchfield Burchfield Cove represents a unique challenge as it is large enough to require significant dredging but not large enough to achieve a significant economy of scale. The short-term prognosis for Burchfield Cove is promising, as the expected completion of the Scott Basin will provide silt storage for two to three decades. Dredging operations should be able to maintain good water depths in this area through 2035, and potentially through 2047. The achievement of new storage should not postpone an aggressive approach to pursuing preventative measures in this watershed. Most notably, streambank erosion should be a priority. Watershed improvements should be pursued as permanent conservation easements to ensure Lake Panorama’s efforts have a lasting effect. ____________________ Other Coves Lake Panorama contains many small coves, which are fed by smaller, local watersheds. These coves contain a much lower volume of silt than their larger counterparts, but are challenging because these are heavily developed and often lack silt storage options. One of the most significant differences regarding the smaller coves is the nature of the silt ponds. In the larger watersheds, silt ponds exist only to receive spoils from dredging operations. In the other coves, silt ponds serve a dual purpose. Silt ponds on many of the smaller coves are located upstream from the cove itself and catch a significant portion of silt before it enters the lake. These retention ponds are effective as a preventative measure against silt accumulation.

Figure 10. Easterly silt ponds and future site.

14

Unfortunately, these retention ponds also have served as Lake Panorama’s only viable storage basin to support dredging operations in small coves. As a result, the retention ponds have received dredging spoils, which has reduced their life expectancy and effectiveness as a preventative buffer structure. The small coves are summarized below with emphasis on retention pond status.

Helen’s Cove is the third largest contributor of silt to Lake Panorama. In 2007, over 9,000

cubic yards of sediment were pumped into a non-preventative silt pond. Only one year later, heavy rains delivered enough silt to negate all of the progress achieved in 2007. Helen’s Cove contains two forks, both of which are currently in need of attention. The main fork of the cove is protected by a three-quarter acre retention pond, which is located on hole #13 of the LPN golf course. Both the retention pond and the main fork are in need of excavation, with the final 450 feet of the main fork being less than four feet deep. An additional retention pond east of Sage Trail would be a valuable addition to this area. The east fork of Helen’s Cove is four feet deep and is accessible to boating. The drainage for this fork is protected by two structures. Immediately upstream is a retention pond which is less than one-tenth of an acre in size. This pond is difficult to access and is in need of maintenance. LPA intends to use a long-stick backhoe to address this in 2012 or 2013. The second silt pond for the east fork is located on LPN’s #15 hole and is approximately 900 feet away from the end of the cove. This pond is approximately one acre and has shown no signs of need for immediate concern. The 2007 dredging operation utilized a one-quarter acre, non-preventative silt pond to store dredging spoils. This project exhausted that pond, which rendered it ineffective for reuse. In preparation for future dredging, LPA has acquired property rights to a site that will support a 50,000 cubic yard silt pond. This pond will be largely non-preventative and will be approximately three acres in size. Construction of this is estimated to occur in 2014 or 2015 and is projected to cost around $200,000. (The $4 cost per cubic yard for storage highlights the inability to achieve economies of scale on smaller coves such as Helen’s.)

Hughes Cove is currently in good condition with five to six feet of water available at the furthest residence. No dredging is anticipated in the near future in Hughes Cove. Hughes Cove has a dual-purpose silt pond, which is located behind the LPA maintenance shop. Dredge spoils were pumped into this structure in the mid-1990s. The structure has very little remaining water depth, and is minimally effective at preventing silt accumulation in Hughes Cove. The current dam for the pond is a berm consisting of clay and broken concrete with no outlet tube. This was designed to be a permeable rock dam and has functioned as such,

15

allowing considerable settling and dewatering. A larger dam with an outlet tube would benefit Hughes Cove and appears to be feasible based upon LPA staff observations.

Lodge Cove is currently in good condition with five feet of water at the rear end of the cove. Lodge Cove is buffered by a dual-purpose structure that is approximately seven acres large. It is too full to be used for a depository of dredging spoils and is only marginally effective as a buffer. The area can be described more as a wetland transition than a retention pond. Unlike some other basins, this structure is not set up to drain water off the stored silt.

The majority of Horseshoe Cove currently is deep enough for boating with little

immediate need for dredging.

The main fork of Horseshoe Cove is extremely narrow at its end and is undeveloped on one side. This has allowed LPA to excavate silt from the shoreline using a long-stick excavator. This has been an effective approach to removing silt and is necessary every three to four years. The north fork of Horseshoe Cove is being excavated using the clamshell barge at the time of this report. Over the course of two months, the barge will remove silt from approximately one-half an acre of lake. Horseshoe Cove is protected by a seven acre, dual-purpose structure known for years as “The Par 3 Pond.” (It now is referred to as the Lake Panorama West Golf Course pond to maintain consistency with the name of the surrounding facility.) Dredge spoils were pumped into the pond in the mid-1990s without exhausting its full depth. This structure remains deep enough to serve as an effective buffer pond and also provides value for fishing and golf course aesthetics. Further pumping into this pond is not advised, as it would reduce its buffering ability and negatively impact the Lake Panorama West Golf Course. The landowner west of Redwood Road has indicated he will be building a private pond for his personal use. This pond will serve as an additional buffer to Horseshoe Cove and will come at no expense to Lake Panorama.

Jones Cove is currently four to five feet deep to the point where private property ends and

LPA community area begins. The bottle neck that extends upstream from this point is narrow, shallow and not intended for boating. No dredging work is currently needed in Jones Cove. Jones Cove is protected by a dual-purpose structure immediately upstream. This structure encompasses approximately 15 acres and is roughly two-thirds filled with silt. A total of 62,000 cubic yards of silt was pumped into this pond in 2005, with approximately 30,000 cubic yards of storage remaining. Further use of this structure for dredging storage would greatly reduce the buffering effect.

16

Periodic maintenance to the community area rip-rap is required to manage the heavy flow that passes through this area. Excavation of the silt structure will eventually be required to ensure it remains effective for retention.

The majority of Andrews Cove is currently deep enough for boating with little immediate

need for dredging. Andrews Cove is well protected by a three and one-half acre retention pond located on private property owned by the Harper family. Harper’s Pond is an effective buffer and is not available to be used for dredge spoils.

Figure 11. Progress clamshell dredging in Dales Cove

Shady Cove has been the focus of ongoing improvement in recent years. The main fork

was excavated using a combination of a long-stick excavator and the clamshell barge. This work has resulted in the main fork being in good condition for boating and silt retention. In addition, a minimal retention pond was constructed to serve the main fork. Maintenance on the retention pond will be necessary every three to four years due to the fact it is less than one-tenth of an acre in size. The south fork is currently very shallow and will require several weeks of clamshell barge excavation in 2013. Retention ponds for the south fork once existed on neighboring property but have since silted in. They currently serve little benefit to the lake. Shady Cove is extremely challenging as the area is poorly suited for retention structures, let alone a basin which would support dredging. Neighboring ground to the south was reviewed by Shive-Hattery in 2010 and it was determined the opportunities for a basin were marginal, at best. Topography in this area was extremely challenging compared with other sections of the lake. The development of a basin to support dredging seems unlikely.

17

Permeable rock dams and small check structures are the most likely improvements which could be explored to modestly slow silt accumulation in Shady Cove.

Dale’s Cove was excavated by the clamshell barge in 2011 and is in excellent condition. The process was extremely inefficient, but was nonetheless effective. Dale’s Cove is adjacent to Shady Cove and possesses many of the same challenges regarding silt pond construction. Dale’s Cove is protected by a retention pond approximately one-tenth of an acre in size. This structure is not large enough to accommodate dredging but is an effective buffer. Access to the retention pond is extremely steep and challenging, requiring the use of a four-wheel drive dump truck. To its advantage, a majority of the Dale’s Cove watershed is used for hay production which greatly reduces siltation into this portion of the lake. Strong Farms, LLC is the owner of this property and voluntarily discontinued row crop production for the benefit of water quality in this area. The value of this preventative approach is significant and should be used as a model for the lake’s other coves. As with Shady Cove, the development of permeable rock dams and small check structures are the most likely improvements which could be explored to modestly slow silt accumulation.

Lake Panorama has dozens of other minor inlets and coves that are prone to siltation. In almost all instances, access is limited to the clamshell barge due to the density of development and the lack of silt basins to support dredging.

Clamshell barge work is effective despite its inherent inefficiencies. Clamshell maintenance is ongoing with the barge being needed in one place or the other at all times. Minor areas that barely appear on the map can consume three to four weeks of full-time excavation to address.

EQUIPMENT

LPA and LP RIZ maintain a fleet of equipment for erosion control. The following is a summary of this hardware and its general condition.

Figure 12. HORIZON dredging in Upper Basin Segment

18

Panorama Horizon: Panorama Horizon was placed into service in 1999 and is the lake’s current dredge. It is a swinging ladder dredge and is designed for large operations, such as Middle Raccoon River and Burchfield Cove dredging. It is currently functioning effectively but is at the end of its useful life. Replacement of Horizon is scheduled tentatively for 2014 or 2015. The dredge is powered by an 860 horsepower Caterpillar 3412E diesel engine with 28,039 hours of use. The engine has been overhauled multiple times and is not suitable to be re-built again. Full scale engine replacement is possible but would prove problematic as emission standards have changed in recent years. A handful of pre-emission standards 3412E engines are still available and would be the simplest option if replacement were required before retirement of Horizon. This was explored in 2011 and is estimated to cost between $100,000 and $120,000. This option hinges on the decreasing availability of the Cat 3412E engine. If necessary, Horizon could be fitted with an engine that conforms to new emissions standards. However, engines that meet new emissions standards burn hotter to reduce pollutants discharged. While this is good for environmental air quality, it is challenging for Horizon as it would require significant modification to the engine cooling system. Cooling system modifications would require professional engineering and could be expensive. This has not been explored as LP RIZ does not intend to replace the engine prior to liquidation of the dredge. Horizon uses a 14” x12” Weir Minerals brand Warman pump, which was installed in 2009. The pump is in good condition, but will require normal maintenance such as periodic replacement of the pump shell and the impeller. It is expected the Horizon will be traded in on a new dredge, or sold outright. Transportation of the dredge to another body of water will be cumbersome and costly. Location could negatively impact its market value during resale as most of the likely buyers are outside of Iowa.

CentreFuse brand Pipe Fusion Machine: This machine was placed into service in 1999 and is used to fuse 50-foot sections of High Density Polyethylene (HDPE) pipe into 300-foot sections. It is capable of fusing 8-inch through 18-inch diameter pipe. It has low hours and is in excellent condition.

Panorama Pride II (“The Deuce”): The Deuce is a 24-foot dredge tender boat placed into service in 1999. It has an A-frame gantry with a small cable winch used for bolting together pipe in the water. It has the capacity of hauling 400 gallons of fuel and is equipped with a high-volume fuel transfer pump. This boat is very maneuverable but lacks versatility beyond support of dredge activities. It is in good condition but is in need of re-painting.

19

Utility Barge Progress: Progress is a 50’ x 14’ barge commissioned in 2009. It is powered by a pair of 230 horsepower Cummins diesel engines and is equipped with a model 12000 Palfinger hydraulic knuckle boom, which provides nearly 35’of reach.

The Palfinger knuckle boom accommodates a grapple attachment for removing logs from the water and a clamshell attachment for excavating silt. Progress is also capable of hauling 800 gallons of fuel to the dredge in the event The Deuce is unavailable. It is in excellent condition and has proved to be an invaluable addition to the fleet.

Figure 13. Progress Barge in transport mode.

Jon Boat: This 14-foot aluminum jon boat is used daily for setting stakes and pulling

debris out of the dredge cutter head. The motor on this boat is currently slated for replacement due to heavy use and wear.

Utility Boat: This 16-foot Crestliner is a hand-me-down security boat, now used for transportation to and from the dredge. This boat is subject to a lot of wear and tear which is reflected in its condition. The motor is in marginal condition but it currently serves its limited purpose.

Pontoon: Three pontoons are used as general work boats for LPA staff. Uses include transporting parts to the dredge, installation of LPA buoys and a variety of other odd jobs. These boats are simple yet sufficient.

Excavator: A 1989 Case 1085C rubber-tired excavator was placed into service at Lake Panorama in 1999 and is used for rip rapping, debris cleanup, and cleaning of ditches. It is in average condition for the 5,700 hours on it.

20

Dump Trucks and other support equipment: LPA maintains a fleet of equipment that includes dump trucks, backhoes and a mini-excavator. All of these items serve as support for erosion control operations and are essential to ensure a fully-equipped fleet.

Figure 14. Single-axle dump trucks, (including four-wheel drive on right) used to haul silt removed by the PROGRESS barge.

Equipment Summary The erosion control fleet is well maintained but most of the equipment is aged. The most important asset, Panorama Horizon, is at the end of its useful life and will require replacement within the next two to three years. Acquisition of a new dredge by 2014 or 2015 is essential to ensure a season is not lost to breakdown or significant repairs. It is anticipated booster pumps will be considered as part of the dredge replacement specifications. Staff is confident engineering analysis will show improved efficiency and reduced wear can be accomplished by implementing at least one booster for use with the County Basin. It should be noted dredging and excavating are aggressive endeavors and result in regular wear of parts and equipment. Routine expenses can be significant, with a $30,000 to $50,000 repair being possible each winter when the dredge is winterized and inspected for wear. REPORT SUMMARY Silt Removal Lake Panorama is generally efficient and effective at silt removal. The current model is working well and should continue without significant challenges provided funding is available for fuel, equipment and labor. Although the current process works well, changes should be embraced as the industry develops new technology and advanced equipment. Silt Storage Silt storage is sufficient for dredging of the Middle Raccoon and Burchfield Cove for roughly the next 20 years, with plans for a Helen’s Cove basin in the near future. All other coves lack silt storage options.

21

The County Basin will physically serve Lake Panorama for another 25 to 30 years but flood easements are only available through 2029. Additional options for silt storage beyond the County Basin should be explored at least six to eight years prior to it being unavailable. Construction of the Scott Basin is expected to be wrapped up in September 2012 and result in 350,000 cubic yards of storage. Historical dredging data suggests this will be a 20-year basin, however, the lease is available through 2047 in the event conservation practices can effectively reduce annual accumulation. Additional options for silt storage beyond the Scott Basin should be explored three to four years prior to it being unavailable. (For perspective, the length of time expected to take the Scott Basin from concept to completion will be about two years.) With the exception of Helen’s Cove, silt storage for the other coves of Lake Panorama is largely unrealistic. Land availability is the major obstacle as many of these areas are densely developed. Dual-purpose structures which have been used for dredge spoils should be cleaned out and allowed to serve as a retention structure for long-term protection of the cove. Dredging into these structures should be discontinued as it merely shifts the silt upstream and lessens the buffering ability of the retention ponds. Dredge spoils continue to be a liability to LPA and LP RIZ with no opportunity for recovery of expenses. Spoils such as sand have limited value to LPA but re-use is not practical due to the costs associated with removal and trucking. Developing a marketable use for dredge spoils seems unlikely, but would be a game-changing development in the funding model for erosion control. Iowa State University has been approached on this issue in the past and continues to represent the most likely source of creative thinking on this topic. Having qualified minds research this topic would require financial commitment from LPA or LP RIZ. Silt Prevention Silt prevention is far more challenging than silt removal and silt storage/retention due to the number of acres and landowners who are encompassed by Lake Panorama’s massive 440 square mile watershed. Improvements to the Middle Raccoon River are a regional challenge and exceed the scope of Lake Panorama, or even Guthrie County. Participation in coalitions such as the South and Middle Raccoon River Watershed Alliance should be pursued for long-term improvement to the watershed. LPA staff believes LPA and LP RIZ should devote the majority of their immediate resources to smaller, local watershed projects such as Burchfield Cove and Helen’s Cove. Efforts in these two watersheds in the next five to ten years are small enough to be achievable and yet large enough to make a measureable difference. Conversations with Guthrie County Soil and Water Conservation should be pursued as the improvement of the Burchfield Cove and Helen’s Cove watersheds represents a natural opportunity for cooperation. These efforts should be quantified and well documented to ensure any successes achieved can serve as a model for the larger Middle Raccoon River watershed. State and Federal funding is

22

most effectively obtained when a proven model has been established. Success in these coves will improve not only the immediate watershed, but also will equip LPA and LPA RIZ to be more effective in the long-term effort of improving the Middle Raccoon River watershed. Cooperation with government entities such as Guthrie County Soil and Water Conservation and Iowa DNR are important avenues to pursue.

Figure 15. This analysis shows modeling of soil movement in the Burchfield Watershed done with the cooperation of the Iowa DNR and LPA

23

Equipment Acquisition of a new dredge is essential due to the aged condition of the Panorama Horizon. At the time of purchase, booster pumps should be considered to reduce wear on the new dredge and allow for dredging of the Fansler Bridge Segment of the Middle Raccoon River. Other equipment will require maintenance and replacement from time to time but expenses pale in comparison to the broader costs of the operation. Replacement of other assets should be built into annual budgets to prevent overwhelming expenses in any one year. Summary Statement Erosion control at Lake Panorama has been ongoing for 30 years and must be continued indefinitely to maintain a sustainable lake. Failure to effectively control erosion would cause Lake Panorama to revert to a river and wetland area within a matter of decades. To achieve sustainable improvement on this issue, sufficient resources must be devoted to both the immediate concern of silt removal and the long-term concern of silt prevention.