Hall Lake Dam (765) 2021 Inspection Report.pdf

CONSTITUTION HALL • 525 WEST ALLEGAN STREET • P.O. BOX 30473 • LANSING, MICHIGAN 48909-7973 Michigan.gov/EGLE • (800) 662-9278

STATE OF MICHIGAN

DEPARTMENT OF

ENVIRONMENT, GREAT LAKES, AND ENERGY

LANSING

VIA E-MAIL

TO: Ron Olson, Chief, Parks and Recreation Division Michigan Department of Natural Resources

FROM: Lucas Trumble, P.E., Supervisor, Dam Safety Unit Water Resources Division

DATE: December 20, 2021

SUBJECT: Hall Lake Dam, Dam ID No. 765; Barry County

Attached is a copy of our Dam Safety Inspection Report and recommendations for the Hall Lake Dam, Dam ID No. 765 located in Barry County. This inspection was completed in accordance with the Memorandum of Understanding between the Michigan Department of Natural Resources (MDNR) and the Michigan Department of Environment, Great Lakes, and Energy [EGLE, formerly Michigan Department of Environmental Quality (MDEQ)], entitled “Inspection of MDNR-Owned Dams and Funding of MDEQ's Dam Safety Program.”

The purpose of this inspection was to evaluate the structural condition and hydraulic capacity of this dam, as required by Part 315, Dam Safety, of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended.

The Hall Lake Dam is in poor condition overall. The poor condition rating of the dam is due to the recent partial failure of the outlet pipe and the sloughing of the downstream slope of the embankment. We are aware of the ongoing project to remediate these issues. When these deficiencies are corrected, the condition rating can be updated.

The inspection report also contains several recommended actions for monitoring and maintenance of deficiencies that do not currently pose a threat to the safety of the dam but should be addressed in the timeframes provided in the report.

Additionally, the Hall Lake Dam is a significant hazard potential dam. As such, the owner is required under Part 315 to prepare, and keep up-to-date, an EAP for the dam.

An EAP has been developed and was last updated on May 22, 2017. The EAP should be reviewed, and updated as necessary, in coordination with Barry County Emergency Management. The owner shall advise the Dam Safety Program of the findings of this review and submit any revisions to the Dam Safety Program by December 31, 2021.

GRETCHEN WHITMER

GOVERNOR

LIESL EICHLER CLARK

DIRECTOR

Ron Olson December 20, 2021

Please contact Mr. Thomas Horak, E.I.T., Dam Safety Program, at 517-231-8594 or HorakT@Michigan.gov, if you have any questions or concerns regarding the inspection report or the recommendations.

Attachment cc: Mr. Andru Jevicks, MDNR

Mr. Brian Kellogg, MDNR Mr. Jim Yarger, Barry County Emergency Management Coordinator Mr. Thomas Horak, EGLE File

DAM SAFETY INSPECTION REPORT

HALL LAKE DAM – DAM ID NO. 765

TRIB TO GUN RIVER

BARRY COUNTY – SECTION 27, T 03N, R 10W

OWNER(S)/OPERATOR(S): Department of Natural Resources Parks and Recreation Division Yankee Springs State Recreation Area 2104 Gun Lake Road Middleville, Michigan 49333 269-795-9081

HAZARD POTENTIAL

CLASSIFICATION: Significant

INSPECTION DATE: July 29, 2021

REPORT DATE: December 20, 2021

PREPARED AND INSPECTED BY:

Thomas Horak, E.I.T.

Dam Safety Unit Water Resources Division Dept. of Environment, Great Lakes, and Energy P.O. Box 30458 Lansing, Michigan 48909 517-231-8594

Lucas A. Trumble, P.E.

Dam Safety Unit Water Resources Division Department of Environment, Great Lakes, and Energy P.O. Box 30458 Lansing, Michigan 48909 517-420-8923

INTRODUCTION

The purpose of this inspection was to evaluate the structural condition and hydraulic capacity of the Hall Lake Dam, as required by Part 315, Dam Safety (Part 315), of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended (NREPA). This inspection was conducted by the Department of Environment, Great Lakes, and Energy (EGLE) per the provisions of its Memorandum of Understanding with the Department of Natural Resources (DNR), the owner of the dam. The report is limited to a discussion of observations based on a visual investigation and review of any available previous inspection reports, plans, and data. This report should not be considered an in-depth engineering investigation. All references to “right” and “left” in this report are based on the observer facing downstream.

CONCLUSIONS AND RECOMMENDATIONS

The Hall Lake Dam is in Poor condition. Dam safety deficiency is recognized for loading conditions which may realistically occur. Remedial action is necessary. Poor rating may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency: further investigations and studies are necessary. The following recommended actions are listed by priority:

1. Continue developing plans for a full remediation of the damaged spillway outlet culvert and submit a permit application for the intended work. Work should include embankment slope restoration and outlet channel realignment in addition to the work on the actual spillway pipe.

2. Repair sloughed area on downstream embankment left of spillway outlet.

Investigate the source and implement necessary preventative measures to protect against future sloughing.

3. Remove all trees and brush from the embankment by December 31, 2021.

Trees and brush should be removed to 10’ beyond groins and from the upstream water surface to 10’ beyond toe of downstream slope. After clearing, the embankment should be mowed or treated with a suitable herbicide a minimum of two times per year to prevent further establishment of woody vegetation and facilitate visual inspection. Trees and brush to be cleared are primarily located at the right upstream end and the left downstream side of the embankment.

4. Monitor for bare spots in the embankment and repair as observed by establishing cover. A bare spot was observed on the right side of the upstream embankment near the right groin.

5. Continue to monitor the seepage along the downstream face of the earthen embankment on a quarterly basis. Report any significant changes in seepage flow rate, colored discharge, or sediment deposition to the Dam Safety Program.

Consider alternative means to controlling seepage on the downstream embankment, such as installing a seepage blanket along the downstream slope.

6. Monitor the undulations/high spots on the downstream embankment near the crest for any changes in geometry or movement.

7. Review, and update as necessary, the dam’s Emergency Action Plan (EAP) in coordination with Barry County Emergency Management. Provide the results of this review, and any updates to the EAP, to the Dam Safety Program by December 31, 2021.

8. Review, and update as necessary, the dam’s Operation and Maintenance (O&M) Plan regularly. Provide updated copies to the Dam Safety Program.

The dam’s current Significant hazard potential rating remains appropriate.

PROJECT INFORMATION

According to our records, the Hall Lake dam was originally constructed in 1964. There are no records of design plans or permits for construction or repair of the dam on file with the Dam Safety Program. The dam, located on an unnamed tributary to the Gun River and owned and operated by DNR Parks and Recreation Division (PRD), creates a recreational impoundment that provides fish and wildlife habitat and swimming and boating opportunities. The dam consists of a 250-foot long earthen embankment and a corrugated metal pipe (CMP) principal spillway structure. The earthen embankment has a crest width of approximately 35 feet, upstream and downstream slopes of approximately 2 horizontal to 1 vertical (2H:1V), and serves as the road bed for Gun Lake Road.

The principal spillway structure consists of a 24-inch diameter CMP inlet riser which discharges through a 24-inch diameter CMP outlet through the earthen embankment.

Impoundment levels are controlled via wooden stoplogs located within the CMP riser structure. It appears that the CMP riser was installed at the upstream end of an existing road culvert. No auxiliary spillway exists at the dam.

The dam has a structural height of 15.3 feet, a hydraulic height of 10.5 feet, and maintains approximately 9.8 feet of head with 5.5 feet of freeboard, creating an approximately 58-acre impoundment under normal flow conditions.

Between 2001 and 2005, as recommended by the 2001 report, filter fabric overlain with riprap was added to the downstream slope of the embankment to control seepage near the spillway outlet. In 2014, the impoundment was temporarily drawn down, up to 4.5 feet, to facilitate repairs to leaking stoplogs in the spillway inlet under Permit No. 14-08- 0065-P. In 2020, the dam’s outlet on the south side of Gun Lake Road failed. An emergency repair was conducted that included removing and replacing the downstream eight feet of pipe. Plans for a full remediation of the outlet structure are being prepared.

The Dam Safety Unit is aware of the project and understands that several of the recommendations and deficiencies pointed out in this report are being addressed in the upcoming project.

The dam was originally inspected by a DNR engineer in 1979. Subsequently, the dam has been inspected by Dam Safety Program under Part 315 in 1993, 2001, 2005, 2009, 2013, and 2017. Copies of these reports, along with engineering sketches of the dam, are on file with the Dam Safety Program, and the 2017 report was used as a reference for this report. Original construction plans for the dam were not available at the time of this inspection.

SITE INVESTIGATION

The following discussion of the dam’s physical condition and appurtenances is based on observations and photographs obtained on the inspection date.

In addition to the specific findings listed below, it is important to continue good maintenance practices. These practices include regular inspection of the dam embankments and hydraulic structures for any deficiencies. Some of the more common issues that are found include growth of trees and brush, development of erosion areas, and animal burrows.

If woody vegetation is allowed to mature, it could develop an extensive root system.

These root systems can lead to piping failure or if the brush and trees are uprooting in a storm, can cause extensive deterioration of the embankment. Embankments should be clear of woody vegetation and mowed 10 feet past the toe of the embankment.

Similarly, animal burrows and surface erosion, can propagate into increased seepage and potentially piping failure, as well as lead to slope stability issues.

The following data was collected on the date of the inspection and includes deficiencies observed during the inspection and necessary actions for remediation of the observed deficiencies.

Upstream Slope

Pool elevation at time of inspection (ft) Not Measured; Slight flow over spillway stoplogs

Upstream slope ground cover Grass

What issues are present on the upstream slope? Brush, Ground Cover Issues

Slope Protection

What types of slope protection are used? Riprap

Average diameter of riprap Type B (12"-24")

Condition of riprap Adequate

Action required for riprap None

Additional comments Some fieldstone riprap present on slope. Slope is stable with sparse riprap

Trees/Woody Vegetation

Brush coverage Sparse

Brush location Right End

\Action required for brush Maintenance

Describe action required Remove trees and brush along entire embankment

Ground Cover / Vegetation Issues

Ground cover type Grass

Ground cover issues Bare

Action required for ground cover Monitor

Describe action required Monitor for bare spots on embankment; repair as necessary

Crest

Approximate width of crest (ft) 35

Approximate freeboard (ft) 5.5

Crest ground cover Road

What issues are present on the crest? None

Additional comments

Gun Lake Rd. is on embankment. A pothole is present beyond the embankment extents left of the embankment and is not considered to be a threat to the safety of the dam

Downstream Slope

Downstream slope ground cover Grass

What issues are present on the downstream slope?

Trees, Brush, Slides, Depressions, Standing Water/Saturated Soil, Uneven areas of embankment with undulations

User Defined Issue

Specify other. Uneven areas of embankment with undulations

Action required for these other issues Monitor

Describe action required Monitor embankment for any changes in geometry. Undulations have not changed from previous inspections.

Trees/Woody Vegetation

Number of trees Dense

Tree DBH (in) 6-12"

Location of trees Left End

Action required for trees Maintenance

Describe action required Remove trees along entire embankment.

Downstream left to right extents of embankment are defined by the line of mature trees on both left and right ends of embankment.

Brush coverage Dense

Location of brush Left End

Action required for brush Maintenance

Describe action required Remove brush on entire embankment

Sliding / Slumping

Approximate transverse length of slides (ft) 10

Approximate longitudinal length of slides (ft) 10

Approximate scarp width (ft) 10

Approximate scarp height (ft) 1

Location of slides Left of downstream culvert outlet near toe

Action required for slides Engineer

Describe action required Repair sloughing and restore embankment, armor against future slides or sloughs. Consider straightening outlet channel to direct water away from toe of embankment

Depressions / Uneven Surface

What is the width of the depressed area (ft)? 20

What is the depth of the depressed area (ft)? 2

Location of the depressed area Upstream of culvert outlet along culvert alignment

Action required for depressions Maintenance

Describe action required Restore embankment to designed slopes during upcoming repair project.

Seepage

Location of standing water/saturated soil Toe

Action required for standing water/saturated soil Monitor, Maintenance

Describe action required Straighten channel; Monitor for changes in seepage; Consider extending seepage blanket along entire downstream slope

Principal Spillway

What type of spillway is present? Pipe & Riser

What is the primary material used in the spillway? Metal

Which components are present? Stoplog, Trash rack

What issues are present with the primary spillway?

Deteriorating Materials, Outlet channel running along toe of embankment creating some instability and allowing embankment to become saturated and slough

User Defined Issue

Specify other. Outlet channel running along toe of embankment creating some instability and allowing embankment to become saturated and slough;

Outlet pipe is also perched

Where are the other issues located? Downstream outlet

Action required for other issues Engineer

Describe action required Relocate channel away from toe of slope with upcoming repair project; Armor channel appropriately if final design includes existing, perched pipe location.

Material Deterioration

What materials are deteriorating in the spillway? Metal

What issues are noted with the metal components?

Rusted Out

Where are the issues located? Outlet

Action required for metal components of the spillway

Engineer

Describe action required Continue development and implement repair of spillway culvert that has been banded after failure.

Restore slopes upon completion of pipe work

Erosion Control / Energy Dissipation

What type of erosion control structure is in place? Rock-Lined Channel

Are there any issues with the outlet erosion control structure?

Alignment of outlet channel

Where are the issues located? Outlet

Action required for other issues Engineer

Describe action required Relocate channel away from toe of slope with upcoming repair project

Gates / Valves

Does the spillway include a gate? No

Other

Security features: Guardrail on both sides of road along crest

Staff gage: None present

The above monitoring and maintenance items should be addressed in accordance with the Conclusions and Recommendations section of this report.

STRUCTURAL STABILITY

Based upon observations during the inspection, there were no indicators of any conditions that represent an immediate threat to the stability of the dam provided the spillway pipe repair project remain in development. However, there is cause for concern of long term stability due to the recent sloughing left of the outlet pipe. The sloughed area is wet, indicating saturation of the embankment is responsible for the slough. This deficiency should be investigated and repaired. Historic seepage at the downstream face of the earthen embankment near the spillway outlet has been previously mitigated by installing non-woven geotextile fabric overlain with graded riprap to function as a filter blanket and prevent migration of embankment fill material.

The principal spillway CMP outlet failed in 2020 at the downstream extent of the pipe. It is assumed the condition of the pipe upstream of the repair is in unsatisfactory condition and should be repaired or replaced. Perforations in the pipe walls and deterioration of pipe joints can lead to loss of embankment materials and eventually breaching of the embankment, a phenomenon known as reverse piping. The outlet pipe was temporarily repaired by replacing several feet of the failed CMP, however the remainder of the outlet pipe remains in poor condition, warranting lining or replacement of the pipe and accounting for the overall poor condition assessment for the dam.

HYDROLOGY AND HYDRAULICS

The contributing drainage area to the unnamed tributary to the Gun River at the Hall Lake Dam is approximately 0.42 square miles. The design discharge for this significant hazard potential dam is the 0.5 percent annual chance (200-year) discharge, which is estimated to be 270 cubic feet per second (cfs). The total runoff volume generated by the design flood event is estimated to be 40 acre-feet. Assuming no discharge through the principal spillway and a straight rise in water levels (both conservative), the entire design flood runoff volume can be stored within the impoundment with a rise in water level of approximately 0.7 feet. Assuming that Hall Lake was at normal pool elevation at the beginning of the flood, a 0.7-foot rise would result approximately 4.8 feet of freeboard at the earthen embankment. Discharge from the principal spillway, assuming 0.7 feet of head over the top of the circular riser, would be approximately 12 cfs. Therefore, the dam is considered to have adequate storage capacity to safely store the entire design flood runoff volume.

Copies of the hydraulic and storage calculations used to make this determination are on file with the Dam Safety Program.

OPERATION AND MAINTENANCE

Operation of the dam is by the PRD staff at the Yankee Springs Recreation Area. An O&M Plan has been developed for this dam. This O&M Plan should be periodically reviewed and updated as necessary. Updated copies should be provided to the Dam Safety Program.

EMERGENCY ACTION PLAN

The Hall Lake Dam is a significant hazard potential dam. As such, the owner is required under Part 315 to prepare, and keep up-to-date, an EAP for the dam. An EAP has been developed and was last updated on May 22, 2017. The EAP should be reviewed, and updated as necessary, in coordination with Barry County Emergency Management. The owner shall advise the Dam Safety Program of the findings of this review and submit any revisions to the Dam Safety Program by December 31, 2021.

APPENDICES

A location map, inspection photographs, and 2021 EGLE estimated flood flows are attached.

Hall Lake Dam Dam ID No. 765 Section 27 T 03N R 10W Barry County

HALL LAKE DAM

BARRY COUNTY

DAM ID NO. 765

Photo #1 - Right upstream groin with brush encroaching past groin onto embankment

Photo #2 - Upstream slope viewed from right end

DAM ID NO. 765

Photo #3 - Upstream slope viewed from crest

Photo #4 - Upstream slope at waterline, minor erosion present

DAM ID NO. 765

Photo #5 - Bare spot near right upstream groin

Photo #6 - Upstream slope viewed from right

DAM ID NO. 765

Photo #7 - Some fieldstone riprap on upstream slope

Photo #8 - Upstream slope viewed from right

DAM ID NO. 765

Photo #9 - Upstream slope viewed from left end. Hydrant near groin (Hydrant installed per Permit No. 10-08-0032-P)

Photo #10 - Crest viewed from left end; Gun Lake Road

DAM ID NO. 765

Photo #11 - Pothole left of embankment extent

Photo #12 - Crest of embankment viewed from left

DAM ID NO. 765

Photo #13 - Crest viewed from right end

Photo #14 - Downstream slope viewed from crest at left groin; Trees and brush have encroached past groin onto embankment

DAM ID NO. 765

Photo #15 - Downstream embankment near crest viewed from left end

Photo #16 - Downstream embankment viewed from left end on crest

DAM ID NO. 765

Photo #17 - View down downstream embankment from crest

Photo #18 - Downstream embankment viewed from left. Note significant depression above spillway outlet.

DAM ID NO. 765

Photo #19 - Sloughed area left of culvert outlet

Photo #20 - Saturated soil downstream of slough

DAM ID NO. 765

Photo #21 - View along downstream embankment. Note low area along alignment of outlet culvert

Photo #22 - Toe of embankment and outlet channel running along toe

DAM ID NO. 765

Photo #23 - View up right groin on downstream embankment

Photo #24 - Downstream slope viewed from right end

DAM ID NO. 765

Photo #25 - Toe of downstream embankment with some uneven grading; Graded riprap filter blanket not observed

Photo #26 - Saturated soil near downstream toe

DAM ID NO. 765

Photo #27 - Sloughed area on downstream embankment

Photo #28 - Toe of downstream embankment viewed from right

DAM ID NO. 765

Photo #29 - Downstream embankment viewed from right; Brush and trees in view to be cleared

Photo #30 - Downstream embankment and outlet culvert viewed from left

DAM ID NO. 765

Photo #31 - Downstream embankment viewed from upstream

Photo #32 - Spillway riser inlet with water over grate

DAM ID NO. 765

Photo #33 - Upstream impoundment

Photo #34 - Zoomed view of riser inlet and trash rack

DAM ID NO. 765

Photo #35 - Outlet of spillway

Photo #36 - Culvert outlet

DAM ID NO. 765

Photo #37 - View up culvert. Repair band location barely noticeable

Photo #38 - Some erosion at outlet pipe

DAM ID NO. 765

Photo #39 - Downstream channel

Photo #40 - Alignment of outlet culvert viewed from downstream

DAM ID NO. 765

Hydrologic Data

From: EGLE-wrd-qreq <EGLE-wrd-qreq@michigan.gov> Sent: Thursday, February 18, 2021 7:39 PM To: Oun, Amira (EGLE) <OunA@michigan.gov> Cc: Trumble, Luke (EGLE) <TrumbleL@michigan.gov> Subject: RE: flood or low flow discharge request (ContentID - 168812)

We have estimated the flood frequency discharges requested in your email of February 4, 2021 (Process No. 20210063), as follows:

Tributary to Gun River at Hall Lake Dam, Dam ID 765, Section 27, T3N, R10W, Yankee Springs Township, Barry County, has a total drainage area of 0.58 square miles and a contributing drainage area of 0.42 square miles. The design discharge for this dam is the 0.5% chance (200-year) flood. The 0.5% chance peak flow is estimated to be 270 cubic feet per second. The 0.5% chance flood volume is estimated to be 40 acre-feet. (Watershed Basin No. 17 Kalamazoo).

Please include a copy of this letter with your inspection report or any subsequent application for permit.

These estimates should be confirmed by our office if an application is not submitted within one year. If you have any questions concerning the discharge estimates, please contact Ms. Susan Greiner, Hydrologic Studies and Dam Safety Unit, at 517-927-3838, or by email at: GreinerS@michigan.gov. If you have any questions concerning the hydraulics or the requirements for the dam safety inspection report, please contact Mr. Luke Trumble of our Dam Safety Program at 517-420-8923, or by email at:

TrumbleL@michigan.gov.

-----Original Message----- From: DoNotReply@michigan.gov <DoNotReply@michigan.gov> Sent: Thursday, February 4, 2021 4:19 PM To: EGLE-wrd-qreq <EGLE-wrd-qreq@michigan.gov> Subject: flood or low flow discharge request (ContentID - 168812)

Requestor: Amira Company: EGLE Address: 0 City: 0 Zip: 00000 Phone: 0000000000 Date: 2021-02-04 F0.5percent: Yes ContactAgency: None Selected ContactPerson:

Watercourse: Tributary to Gun River LocalName:

CountyLocation: Barry CityorTownship: ?

mailto:EGLE-wrd-qreq@michigan.gov mailto:OunA@michigan.gov mailto:TrumbleL@michigan.gov mailto:GreinerS@michigan.gov mailto:TrumbleL@michigan.gov mailto:DoNotReply@michigan.gov mailto:DoNotReply@michigan.gov mailto:EGLE-wrd-qreq@michigan.gov

DAM ID NO. 765

Section: 27 Town: 03N Range: 10W Location: Hall Lake Dam #765 FFR1: Dam fpReqEmailAddr: OunA@michigan.gov mailto:OunA@michigan.gov