EMERGENCY TRANSPORTATION INFRASTRUCTURE RECOVERY WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES
MOYER CREEK HERKIMER COUNTY, NEW YORK
April 2014
MMI #5231-01
Photo Source: Milone & MacBroom, Inc. (2013)
This document was prepared for the New York State Department of Transportation, in cooperation with the New York State Department of Environmental Conservation.
Prepared by:
MILONE & MACBROOM, INC. 134 Main Street, Suite A1 New Paltz, NY 12561 (845) 633-8153 www.miloneandmacbroom.com
Copyright 2014 Milone & MacBroom, Inc. TABLE OF CONTENTS Page
1.0 INTRODUCTION ...... 1
1.1 Project Background ...... 1 1.2 Nomenclature ...... 3
2.0 DATA COLLECTION ...... 3
2.1 Initial Data Collection ...... 3 2.2 Public Outreach ...... 3 2.3 Field Assessment ...... 3 2.4 Watershed Land Use ...... 5 2.5 Geomorphology ...... 5 2.6 Hydrology ...... 8 2.7 Infrastructure ...... 10
3.0 FLOODING HAZARDS AND MITIGATION ALTERNATIVES ...... 12
3.1 Flooding History along Moyer Creek ...... 12 3.2 Post-Flood Community Response ...... 15 3.3 Flood Mitigation Analysis ...... 15 3.4 High Risk Area #1 – Road Crossings in Frankfort Gorge ...... 16 3.5 High Risk Area #2 – High Bank Failure and Levees ...... 18 3.6 High Risk Area #3 – Main Street Bridge, Canal Walls, and Existing Dam ...... 21
4.0 RECOMMENDATIONS ...... 27
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 TC - i TABLE OF CONTENTS (continued)
Page LIST OF TABLES
Table 1 Estimated Bankfull Discharge, Width, and Depth ...... 8 Table 2 Moyer Creek Peak Discharges at its Confluence with the Mohawk River ...... 9 Table 3 Moyer Creek Peak Discharges 1,800 Feet Downstream of the Intersection With Route 171 and Furnace Road ...... 10 Table 4 Final Hydrology for HEC-RAS Modeling of Moyer Creek ...... 10 Table 5 Summary of Stream Crossing Data ...... 11 Table 6 Summary of Important Elevations ...... 23 Table 7 Cost Range for Recommended Alternatives ...... 30
LIST OF FIGURES
Figure 1 Moyer Creek Drainage Basin Location Map ...... 2 Figure 2 Moyer Creek Watercourse Stationing ...... 4 Figure 3 Moyer Creek Drainage Basin Aerial...... 6 Figure 4 Moyer Creek Profile ...... 7 Figure 5 FEMA Delineated Floodplain ...... 13 Figure 6 Moyer Creek High Risk Area #1 – Road Crossings in Frankfort Gorge ...... 17 Figure 7 Moyer Creek High Risk Area #2 – High Bank Failure and Levees ...... 19 Figure 8 Moyer Creek High Risk Area #3 – Main Street Bridge, Canal Walls, and Existing Dam ...... 22 Figure 9 Hydraulic Modeling of Dam Removal and Main Street Bridge Replacement ...... 24
LIST OF APPENDICES
Appendix A Summary of Data and Reports Collected Appendix B Field Data Collection Forms Appendix C Moyer Creek Photo Log Appendix D Detention Basin Computations
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 TC - ii ABBREVIATIONS/ACRONYMS
BIN Bridge Identification Number CFS Cubic Feet per Second CME Creighton Manning Engineering D/S Downstream FEMA Federal Emergency Management Agency FIRM Flood Insurance Rate Map FIS Flood Insurance Study FT Feet FTP File Transfer Protocol GIS Geographic Information System HEC-RAS Hydrologic Engineering Center – River Analysis System LiDAR Light Detection and Ranging MMI Milone & MacBroom, Inc. NOAA National Oceanic and Atmospheric Administration NWS National Weather Service NYSDEC New York State Department of Environmental Conservation NYSDOT New York State Department of Transportation SQ. MI. Square Mile STA River Station USACE United States Army Corps of Engineers USGS United States Geological Survey WSEL Water Surface Elevation YR Year
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 TC - iii 1.0 INTRODUCTION
1.1 Project Background
A severe precipitation system in June 2013 caused excessive flow rates and flooding in a number of communities in the greater Utica region. As a result, the New York State Department of Transportation (NYSDOT) in consultation with the New York State Department of Environmental Conservation (NYSDEC) retained Milone & MacBroom, Inc. (MMI) through a subconsultant agreement with Creighton Manning Engineering (CME) to undertake an emergency transportation infrastructure recovery water basin assessment of 13 watersheds in Herkimer, Oneida, and Montgomery Counties, including the Moyer Creek watershed. Prudent Engineering was also contracted through CME to provide support services, including field survey of stream cross sections.
Moyer Creek flows through the towns of Litchfield and Frankfort and the village of Frankfort in Herkimer County, New York. Figure 1 depicts the contributing watershed of the creek. Moyer Creek drains an area of 20 square miles. The drainage basin is approximately 47.5 percent forested, with rural residential and agriculture land uses. Residential and commercial land uses are concentrated in the lower part of the basin in the village of Frankfort. The creek has an average slope of 1.5 percent over its stream length of 12.7 miles.
Though it not severely steep, Moyer Creek generates a substantial amount of stream power, especially as it flows through the steep Frankfort Gorge, where the channel has a slope of 2.0 percent. Sediments transported from the upper reaches of the creek are moved to the lower gradient reaches in the village of Frankfort, where they are deposited in the channel, restricting flow capacity and blocking stream crossings.
Compounding the issues of sediment transport and stream hydraulics is the fact that commercial and residential development in the village of Frankfort occurs in the floodplain, in some cases to within 20 feet of the edge of the stream. When the channel exceeds its hydraulic capacity or becomes clogged with sediment debris, it finds new and destructive paths through the community, leaving homes and property damaged by floodwaters, bridges damaged, and unstable creek bed and banks that are at risk for further degradation and failure.
The goals of the subject water basin assessment were to:
1. Collect and analyze information relative to the June 28, 2013 flood and other historic flooding events.
2. Identify critical areas subject to flood risk.
3. Develop and evaluate flood hazard mitigation alternatives for each high risk area within the stream corridor.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 1 Copyright:© 2013 National Geographic Society, i-cubed SOURCE(S): Map By: CMP Figure 1: Moyer Creek Drainage NYDOT: Emergency Transportation MMI#: 5231-01 Infrastructure Recovery Original: 1/2/2014 99 Realty Drive Cheshire, CT 06410 Basin Location Map Revision: 3/19/2014 (203) 271-1773 Fax: (203) 272-9733 ³ MXD: Y:\5231-01\GIS\Maps\Figure 1 Maps\Figure 1 Moyer Creek.mxd LOCATION: Herkimer County, New York Scale: 1 in = 5,000 ft www.miloneandmacbroom.com 1.2 Nomenclature
In this report and associated mapping, stream stationing is used as an address to identify specific points along the watercourse. Stationing is measured in feet and begins at the mouth of Moyer Creek at STA 0+00 and continues upstream to STA 680+00. As an example, STA 73+00 indicates a point in the channel located 7,300 linear feet upstream of the mouth. Figure 2 depicts the stream stationing along Moyer Creek.
All references to right bank and left bank in this report refer to "river right" and "river left," meaning the orientation assumes that the reader is standing in the river looking downstream.
2.0 DATA COLLECTION
2.1 Initial Data Collection
Public information pertaining to Moyer Creek was collected from previously published documents as well as through meetings with municipal, county, and state officials. Data collected includes reports, photographs, newspaper articles, Federal Emergency Management Agency (FEMA) Flood Insurance Studies (FIS), aerial photographs, and geographic information system (GIS) mapping. Appendix A is a summary listing of data and reports collected.
2.2 Public Outreach
An initial project kickoff meeting was held in early October 2013 with representatives from NYSDOT and NYSDEC, followed by public outreach meetings held in the affected communities, including a meeting held in the village of Frankfort to discuss Moyer Creek. These meetings provided more detailed, firsthand accounts of past flooding events; identified specific areas that flooded in each community and the extent and severity of flood damage; and provided information on post-flood efforts such as bridge reconstruction, road repair, channel modification, and dredging. This outreach effort assisted in the identification of target areas for field investigations and future analysis.
2.3 Field Assessment
Following initial data gathering and outreach meetings, field staff from Prudent Engineering and MMI undertook field data collection efforts, with special attention given to areas identified in the outreach meetings. Initial field assessment of all 13 watersheds was conducted in October and November 2013. Selected locations identified in the initial phase were assessed more closely by multiple field teams in late November 2013. Information collected during field investigations included the following:
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Figure 2 . Rapid "windshield" river corridor inspection . Photo documentation of inspected areas . Measurement and rapid hydraulic assessment of bridges, culverts, and dams . Geomorphic classification and assessment, including measurement of bankfull channel widths and depths at key cross sections . Field identification of potential flood storage areas . Wolman pebble counts . Cohesive soil shear strength measurements . Characterization of key bank failures, headcuts, bed erosion, aggradation areas, and other unstable channel features . Preliminary identification of potential flood hazard mitigation alternatives, including those requiring further analysis
Included in Appendix B is a copy of the River Assessment Reach Data Form, River Condition Assessment Form, Bridge Waterway Inspection Form, and Wolman Pebble Count Form. Appendix C is a photo log of select locations within the river corridor. Field Data Collection Index Summary mapping has been developed to graphically depict the type and location of field data collected. Completed data sheets, field notes, photo documentation, and mapping developed for this project have been uploaded onto the NYSDOT ProjectWise system and the project-specific file transfer protocol (FTP) site at MMI. The data and mapping were also provided electronically to NYSDEC.
2.4 Watershed Land Use
Figure 3 is a watershed map of Moyer Creek. The creek flows through the towns of Litchfield and Frankfort and the village of Frankfort, in Herkimer County. The creek can be broken into three sections based on land use and channel slope. In the upper part of the watershed, from its headwaters to the confluence with Black Creek (STA 457+00), land uses consist of a patchwork of forested, agricultural, and rural residential uses. From its confluence with Black Creek (STA 457+00) downstream to Route 5S (STA 63+00), land uses consist of a mix of forested, agricultural, and rural residential uses. The stream corridor through Frankfort Gorge is primarily forested. The lower portion of Moyer Creek, from Route 5S (STA 63+00) to its mouth at the Mohawk River (STA 0+00), flows through the village of Frankfort for a distance of 1.2 miles. Land uses consist of residential and commercial land uses concentrated in the lower part of the basin in the village of Frankfort.
2.5 Geomorphology
Moyer Creek shows evidence of high sediment load in the main channel and tributaries. In the upper part of the watershed, from its headwaters to the confluence with Black Creek (STA 457+00), Moyer Creek has a relatively flat gradient, with a slope of 0.8 percent. The creek's elevation drops from 1,462 feet above sea level at its headwaters to an elevation of 1,259 feet at its confluence with Black Creek, a change of 203 feet over 4.7 miles.
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Figure 3 From its confluence with Black Creek (STA 457+00) downstream to Route 5S (STA 63+00), a distance of 7.5 miles, Moyer Creek flows through the steeper Frankfort Gorge, which has a slope of 2.0 percent. Within this section, Moyer Creek falls 792 vertical feet, from 1,259 feet above sea level to 466. This steep portion of Moyer Creek has more energy than low gradient streams and, as a result, has higher velocities and is able to carry more sediment.
The lower portion of Moyer Creek, from Route 5S (STA 63+00) to its mouth at the Mohawk River (STA 0+00), drops 82 feet over this distance and has a slope of 1.3 percent.
Figure 4 presents a profile of Moyer Creek, showing the watercourse elevation versus the linear distance from the mouth of the watercourse. Frankfort Gorge and the Main Street bridge are shown on the profile to provide context.
FIGURE 4 Moyer Creek Profile
1500 1400 1300 1200 1100 1000 900 800
Elevation Elevation (feet) Frankfort Gorge 700 600 500 400 Main St. 300 800+00 700+00 600+00 500+00 400+00 300+00 200+00 100+00 0+00 Watercourse Stationing (linear distance from mouth, in feet)
It is evident that the stream channel has been recently dredged within some reaches to remove accumulated sediment. In some of these areas, dredged materials have been placed directly on the stream banks or in the floodplain.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 7 At various points along its length as it flows through the village of Frankfort, Moyer Creek has been lined by stacked rock and concrete block walls. A new stacked rock revetment wall has been constructed at the base of the large bank failure on the left bank, from STA 51+00 downstream to STA 46+00. An earthen levee is situated on the right creek bank adjacent to the senior living facility, between STA 43+50 and STA 39+50. The levee sustained damaged during the June 2013 flood. Approaching the Main Street bridge, the channel is lined on both sides by stone walls.
2.6 Hydrology
Alluvial river channels adjust their width and depth around a long-term dynamic equilibrium condition that corresponds to "bankfull" conditions. Extensive data sets indicate that the channel-forming or bankfull discharge in specific regions is primarily a function of watershed area and soil conditions. The bankfull width and depth of alluvial channels represent long-term equilibrium conditions and are important geophysical criteria that are used for design. Table 1 below lists estimated bankfull discharge, width, and depth at several points along Moyer Creek, as derived from the United States Geological Survey (USGS) StreamStats program.
TABLE 1 Estimated Bankfull Discharge, Width, and Depth (Source: USGS StreamStats)
Watershed Area Discharge Bankfull Bankfull Location along Moyer Creek Station (sq. mi.) (cfs) Width (ft) Depth (ft) Downstream of Furnace Road 238+00 13.4 418 43.3 2.16 Swimming Road 34+00 19.9 586 51.7 2.5 Mouth of Moyer Creek 0+00 20.0 589 51.8 2.51
Actual bankfull widths measured on Moyer Creek were compared to the regional bankfull channel dimensions reported above. The measured bankfull width in Frankfort Gorge (at STA 142+00) was 48 feet compared to the regional bankfull channel width of 43.3 feet. The measured bankfull width at the senior living facility (STA 42+00) was 43 feet in contrast to the regional bankfull channel width of 51.7 feet, indicating that the channel is undersized at this location. In contrast, bankfull measurements taken at the recently repaired high bank failure (STA 51+00) showed a bankfull width of 116 feet, indicating that the channel is overly wide at this location.
There are no USGS stream gauging stations on Moyer Creek. Hydrologic data on peak flood flow rates are available from the FEMA FIS and from StreamStats regional data. A preliminary draft FEMA FIS for all of Herkimer County was issued on September 30, 2011 but had not been formally approved as of the publication of the subject document.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 8 According to this draft FIS, the most recent hydraulic modeling for Moyer Creek dates from December 2004.
The hydrologic analysis methods employed in the FEMA study used standardized regional regression equations detailed in USGS publication 90-4197 Regionalization of Flood Discharges for Rural, Unregulated Streams in New York, Excluding Long Island, (USGS, 1991). This regression analysis uses parameters such as mean annual precipitation and several watershed characteristics to estimate flow frequencies. FEMA applied these discharges in a backwater analysis of Moyer Creek, compared the resulting water surface elevations with historical elevations, and checked for reasonableness. The results were published in the FIS, and the resulting mapping was published as the effective Flood Insurance Rate Map (FIRM) for Herkimer County.
Estimated peak discharges for various frequency events were calculated by MMI using StreamStats and compared to peak discharges reported in the draft FEMA FIS. Table 2 lists estimated peak flows at Moyer Creek's confluence with the Mohawk River, which is located at STA 0+00. The drainage area at this location is reported in the FEMA FIS to be 20.4 square miles and by StreamStats to be 20.0 square miles.
TABLE 2 Moyer Creek Peak Discharges at its Confluence with the Mohawk River (Station 0+00)
Peak Discharge, Peak Discharge, Frequency FEMA (cfs) StreamStats (cfs) 10-Yr 1,100 1,720 50-Yr 1,620 2,510 100-Yr 1,850 2,900 500-Yr 2,400 3,820
Table 3 lists estimated peak flows approximately 1,800 feet downstream of the intersection of Route 171 and Furnace Road, at STA 237+00. The drainage area at this location is reported in the FEMA FIS to be 13.8 square miles and by StreamStats to be 13.4 square miles.
It is noteworthy that the flows reported by FEMA at the upstream location (STA 237+00) exceed those reported at the downstream location (STA 0+00). This should not be the case and is likely due to an error in the FEMA report. It is possible that the two cross sections were inadvertently swapped in the FEMA report.
Both FEMA and StreamStats discharges were used in a preliminary hydraulic model to determine which set would better represent known flooding conditions. The results of this comparison led to the conclusion that the discharges produced by StreamStats reflect
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 9 conditions during the June 2013 flooding more accurately than discharges estimated by FEMA. Therefore, these were selected for use in the hydraulic analyses.
TABLE 3 Moyer Creek Peak Discharges 1,800 Feet Downstream of the Intersection with Route 171 and Furnace Road (Station 237+00)
Peak Discharge, Peak Discharge, Frequency FEMA (cfs) StreamStats (cfs) 10-Yr 1,510 1,220 50-Yr 2,210 1,780 100-Yr 2,520 2,060 500-Yr 3,260 2,720
StreamStats flows were generated at relevant locations in the model and at confluences with larger tributaries. Table 4 reflects the flows that were used in the Hydrologic Engineering Center – River Analysis System (HEC-RAS) model.
TABLE 4 Final Hydrology for HEC-RAS Modeling of Moyer Creek
Bankfull 10-Yr 50-Yr 100-Yr 500-Yr Station Flow (cfs) Flow (cfs) Flow (cfs) Flow (cfs) Flow (cfs) 79+45 576 1,670 2,440 2,820 3,710 27+45 568 1,710 2,500 2,890 3,800
2.7 Infrastructure
As Moyer Creek flows through the Frankfort Gorge, Route 171 crosses over the watercourse a total of seven times within a distance of 3.6 miles between STA 274+00 and STA 82+00. The creek also crosses Brice Road. Many of these bridge crossings have poor alignment with the creek, and the bridges and the roads have been damaged by floods.
Some of the worst flooding on Moyer Creek has occurred in the vicinity of the Main Street bridge (STA 16+00). According to community officials, during the June 2013 flood, waters from Moyer Creek crested over Main Street at the bridge, ran through yards and damaged buildings, and then ran back into Moyer Creek downstream of Main Street. The FEMA flood profile shows this bridge as a constriction, further exacerbated by ice accumulations in the winter. Recent reports indicate that the Main Street bridge almost overtopped due to an ice jam in early January 2014.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 10 Bridge spans and heights were measured as part of the 2013 field investigations. Table 5 summarizes the bridge measurements collected. For purposes of comparison, estimated bankfull widths at each structure are also included. These indicate that nearly all of the bridge crossings fail to span the bankfull width of Moyer Creek. Adequately sized stream crossings not only have the potential to reduce flooding, they also provide a range of environmental benefits by allowing aquatic organisms, sediment, and debris to be conveyed through the stream corridor.
TABLE 5 Summary of Stream Crossing Data
Bankfull Roadway Crossing Station BIN Width (ft) Height (ft) Width (ft) Gulf Road 344+00 --- 19.5 6.4 – 7.6 34.9 Route 171 East of Ball Road 340+50 000000001039060 25.0 12.0 35.9 Route 171 West of Fish Road 274+00 000000001039070 48.5 2.0 – 8.4 37.8 Route 171 West of Furnace 266+00 000000001039080 24.9 --- 38.3 Road Route 171 East of Furnace Road 235+50 000000001039090 25.0 9.0 43.3 Route 171 East of private drive 187+00 000000001039100 81.0 3.1 – 5.0 44.0 Route 171 D/S of parking area 148+00 000000001039110 40.0 8.9 – 11.0 49.7 Route 171 West of Brice Road 134+00 000000001039120 46.0 6.3 – 7.3 50.0 Brice Road 96+50 000000002255580 ------50.9 Route 171 East of Brice Road 82+00 000000001039130 85.5 4.0 – 13.4 50.9 Route 5S-2 63+00 000000001051241 ------51.4 Route 5S-1 62+00 000000001051242 ------51.4 Swimming Road 34+00 000000002263710 46.0 9.8 – 11.9 51.7 West Main Street 16+00 000000002263720 34.0 5.0 – 5.3 51.8
Flood profiles published in the FEMA FIS were evaluated to determine which bridges on Moyer Creek are acting as hydraulic constrictions during large flood events and which bridges overtop during these events, based on FEMA modeling for the 10-, 50-, 100-, and 500-year frequency flood events. The FEMA profiles extend upstream only as far as the Route 171 bridge crossing at STA 134+00. The profiles indicate that the bridge at the Route 171 crossing at STA 134+00 acts as a moderate hydraulic constriction during the 10-year flood event and as a substantial hydraulic constriction during the 50-year event and larger. The profiles indicate that this bridge overtops during the 500-year event. The FEMA flood profile also shows the railroad bridge downstream of Main Street as a major constriction. This bridge was removed subsequent to the FEMA study.
The Brice Road bridge (STA 96+50) is shown to act as a moderate hydraulic constriction during the 10-year flood event and larger and does not overtop. Neither the Route 171 crossing at STA 82+00, the Route 5S bridge (STA 63+00), nor the Swimming Road
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 11 bridge (STA 34+00) act as hydraulic constrictions, and none of them is predicted to overtop during any of the FEMA modeled flood events. The Main Street bridge (STA 16+00) acts as a moderate hydraulic constriction during the 10-year flood and a substantial constriction during the 50-, 100-, and 500-year flood events. The FEMA profiles indicate that floodwaters overtop the Main Street bridge during the 100- and 500- year flood events.
The FEMA profiles indicate that the dam located just downstream of the Main Street bridge (STA 13+00) creates a backwater condition that extends upstream to the Main Street bridge. The backwater from the Mohawk River extends upstream as far as the dam.
3.0 FLOODING HAZARDS AND MITIGATION ALTERNATIVES
3.1 Flooding History Along Moyer Creek
The most severe historic flood-related damages on Moyer Creek have occurred to the road and bridges in Frankfort Gorge; in the vicinity of the Edgebrook Estates trailer park and the senior living facility; and in the vicinity of the Main Street bridge. Large volumes of sediment and large woody debris are conveyed down the creek from higher in the watershed during high flow events. This material is deposited in the channel, which reduces the channel capacity and exacerbates flooding.
Historic photos provided by municipal officials show the formation of an ice jam at the Main Street bridge in February 1981. Floodwaters and ice overtopped the bridge, flooding Main Street, the intersection of Main Street and Mill Street, and the mill building on Mill Street. During the 1981 flood, the Main Street bridge appears to have become completely clogged by ice. Heavy equipment was used to remove the ice jam from the creek. Photos also show a severe flood event in August 1996 that caused extensive damage to properties and road crossings along Route 171 and Gorge Road.
A Moyer Creek flood damage control feasibility study produced by the U.S. Army Corps of Engineers in April 2005 reports that the Moyer Creek Basin has historically experienced flooding events and has had major floods recorded as early as 1904. Many of the flooding events are reported to be related to ice jamming conditions that result in the backup of water and overbank flooding. The study lists major flood events on Moyer Creek, including September 1938, June 1972, February 1981, February 1994, February 1996, August 1996, and March 2003.
FEMA FIRMs for Moyer Creek are available for the village of Frankfort. FEMA mapping (Figure 5) indicates that, during the 100-year frequency flood event, water from Moyer Creek becomes ponded upstream of the Main Street bridge and floods homes and businesses along the southwest side of Main Street, extending northwest beyond Route 96 (Cemetery Street) and southeast beyond Route 171 (South Litchfield Street), as well as on some of the side streets in this area.
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Watercourse Figure 5 According to the FEMA maps, floodwaters also overtop the banks on both sides of Moyer Creek downstream of Main Street, in the vicinity of the dam at STA 13+00.
The FEMA flood insurance study reports that ice jams are often the cause of flooding on Moyer Creek. An ice jam occurred on Moyer Creek on March 18, 2003. According to the FEMA study, the town of Frankfort has no structural flood protection measures that are capable of significantly reducing damage from floodwaters.
In mid to late June and early July 2013, a severe precipitation system caused excessive flow rates and flooding in a number of communities in the greater Utica region, including in the Moyer Creek Basin. Because rainfall across the region was highly varied and rainfall information is limited, it is not possible to determine exact rainfall amounts within the Moyer Creek Basin.
Records on the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) Advanced Hydrologic Prediction Service website indicate that the village of Frankfurt area received between 10 and 15 inches of rainfall in the month of June and an additional 5 to 8 inches in July 2013. Much of this rainfall occurred over several storm events that dropped between 3.5 and 4.5 inches of rain between June 11 and June 14; 5.5 to 8.5 inches between June 24 and June 28; and 1.5 to 2.0 inches on July 2. In between these more severe rain events were a number of smaller rain showers that dropped trace amounts of precipitation, preventing soils from drying out between the larger rain events.
Edgebrook Estates is a mobile home park located close to the watercourse in the vicinity of STA 57+00 downstream to STA 53+00. Community officials report that flood damage to several of the mobile homes occurred in this area during the June 2013 flood. They also reported that, to their knowledge, this was the first time that Edgebrook Estates had ever flooded. FEMA mapping indicates that Edgebrook Estates is located just outside of the 100-year frequency flood zone.
A high bank failure is located between STA 48+00 and STA 51+00, which threatens the athletic fields at the top of the bank. According to village officials, this bank had been gradually failing for quite some time prior to the June 2013 flood but was made much worse during the flood. Repair work was undertaken immediately following the flood to stabilize the slope by creating a stacked rock wall along the edge of the stream, at the toe of the bank failure. Erosion caused by the flood exposed a groundwater seep on the bank failure that is tending to keep the slope wet and is likely contributing to bank sliding.
A senior living facility (made up of three sets of buildings known as Streamside Manor, Litchfield Manor, and the Campus Apartments) is located on the right bank between STA 45+00 and STA 39+00. An earthen levee is situated between Moyer Creek and the buildings. According to community officials, during the June 2013 flood Moyer Creek came very close to overtopping the levee but did not overtop it. During the flood, the levee sustained damage due to erosion.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 14
Some of the worst flooding on Moyer Creek occurred at the Main Street bridge (STA 16+00). Waters from Moyer Creek crested over Main Street, ran through yards and damaged buildings, and then ran back into Moyer Creek downstream of Main Street.
3.2 Post-Flood Community Response
Following the heavy flooding in June 2013 along Moyer Creek, the Town of Frankfort implemented numerous temporary repairs. Private property owners throughout the village attempted repairs to individual sections of stream bank as well.
The downstream most segment of Moyer Creek as it flows into the Mohawk River is subject to high levels of aggradation as the creek enters the backwater floodplain of the Mohawk River. The reach from the confluence to the dam above Main Street was dredged after the June 2013 floods. Sediment that was removed from the channel was sidecast onto the adjacent banks (STA 0+00 to STA 14+00).
According to local officials, the high bank failure adjacent to the athletic fields was made much worse during the June 2013 flood. Repair work was undertaken immediately following the flood to stabilize the slope by creating a stacked rock wall along the edge of the stream.
A large forested floodplain is located upstream of Route 5S and adjacent to Brookside Drive that was damaged during the floods. A site restoration was implemented, which appeared to create a bankfull channel and restore a gradually sloping floodplain through the reach using accumulated sediment.
3.3 Flood Mitigation Analysis
Hydraulic analysis of Moyer Creek was conducted using the HEC-RAS program. The HEC-RAS computer program (River Analysis System) was written by the United States Army Corps of Engineers (USACE) Hydrologic Engineering Center (HEC) and is considered to be the industry standard for riverine flood analysis. The model is used to compute water surface profiles for one-dimensional, steady-state, or time-varied flow. The system can accommodate a full network of channels, a dendritic system, or a single river reach. HEC-RAS is capable of modeling water surface profiles under subcritical, supercritical, and mixed-flow conditions.
Water surface profiles are computed from one cross section to the next by solving the one-dimensional energy equation with an iterative procedure called the standard step method. Energy losses are evaluated by friction (Manning's Equation) and the contraction/expansion of flow through the channel. The momentum equation is used in situations where the water surface profile is rapidly varied, such as hydraulic jumps, mixed-flow regime calculations, hydraulics of dams and bridges, and evaluating profiles at a river confluence.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 15
Hydraulic modeling, originally generated by FEMA as part of a 2004 study of Moyer Creek, was obtained and used as a starting point for this analysis. It can be assumed that conditions have significantly changed since the date of the FEMA study and, for that reason, updated cross sections were surveyed as part of the subject analysis. The updated survey information was incorporated into the hydraulic model in order to better characterize and understand modern flooding risks and causes.
The survey effort included the wetted area (within bankfull elevation) of 16 stream cross sections, plus the survey of three bridges/culverts. This data was combined with countywide light detection and ranging (LiDAR) data provided by the NYSDEC to develop sufficient model geometry such that existing conditions flooding up to and including the 100-year recurrence interval could be modeled.
As indicated in Section 2.6, given the discrepancies in the FEMA hydrology (i.e., upstream flows higher than downstream flows) and the comparison of flows to observed field conditions, StreamStats hydrology was used for purposes of modeling flood mitigation alternatives.
The model of existing conditions was then used to hydraulically model certain alternatives, described further in the report sections that follow. Model input and output files have been uploaded onto the NYSDOT ProjectWise site and have been delivered electronically to NYSDEC.
3.4 High-Risk Area #1 – Road Crossings in Frankfort Gorge (STA 80+00 to STA 280+00)
Figure 6 is a location plan of High Risk Area #1. This area includes the portion of Frankfort Gorge in which Route 171 crosses over Moyer Creek seven times within a distance of 3.6 miles. The creek also crosses Brice Road at STA 97+00. This reach of Moyer Creek has an average gradient of 2.0 percent. Many of the bridge crossings have very poor alignment with the creek, and the bridges and the roads have been damaged by floods. Most of these bridges do not span the bankfull width. The FEMA flood profile shows that some of these bridges are acting to constrict flood flows. The undersized bridges along Route 171 include east of Ball Road (STA 340+50), west of Furnace Road (STA 266+00), east of Furnace Road (STA 235+50), downstream of parking area (STA 148+00), and west of Brice Road (STA 134+00).
Also within this High Risk Area at STA 159+00, a tributary enters Moyer Creek. Prior to entering the creek, the tributary flows through a culvert under Route 171. During storm events, the culvert becomes clogged with debris, causing flows to overtop Route 171. Route 171 provides access to the Frankfort Airport, the town of Litchfield, and points southwest of the village of Frankfort. Because of the gorge, access is limited to these areas. During a flood event in which any of the seven Route 171 bridges crossing Moyer Creek is damaged or otherwise impassible, emergency services have a very long detour to reach destinations past the gorge.
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Alternative 1-1: Replacement of Bridges as Necessary with Properly Sized Structures
Replacement of undersized bridges that cross Moyer Creek along Route 171 would better protect infrastructure (i.e., bridges and roads). Due to the steepness of the gorge, adjacent developed areas do not exist. As part of the New York State roadway system, these bridge crossings are regulated by NYSDOT. Replacement of all of the bridges in Frankfort Gorge may be too costly to pursue at once; however, the state may wish to pursue a long-term replacement plan to address these bridges as they are scheduled for rehabilitation or replacement.
Alternative 1-2: Realignment of Creek to Avoid Stream Crossings
An alternate method of mitigating flooding associated with undersized crossings is to eliminate certain crossings through roadway realignment. The challenging topography associated with the gorge will make realignment difficult, but it should be considered as part of a master plan for this reach.
Recommendation
Replacement or elimination of undersized bridges is recommended along Route 171 as a comprehensive long-term flood mitigation program. A detailed assessment of these bridges should be performed in order to provide a ranking and a plan for their eventual replacement.
3.5 High-Risk Area #2 – High Bank Failure and Levees (STA 34+00 to STA 52+00)
Figure 7 is a location plan of High Risk Area #2. The village of Frankfort was developed primarily in the low-lying floodplain area of Moyer Creek at its confluence with the Mohawk River. A small area to the west of the village is situated on a plateau overlooking the remainder of the village. This plateau supports agricultural land use, athletic fields, and some light residential development.
As Moyer Creek flows along the western edge of the village of Frankfort, it encounters the base of this plateau (STA 52+00 to STA 47+00), where it began eroding the valley wall and caused a significant bank failure to occur. This bank failure was a major source of sediment for Moyer Creek. A stabilization project was recently implemented at this location and at the time of inspection appeared to have arrested the active erosion. This will reduce the sediment supply and downstream deposition during future floods. The stream through this reach is overly wide. Monitoring of this site is recommended to ensure that aggradation of sediment does not compromise the function of the levee.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 18 High Bank Failure with recently constructed revetment wall
Senior Living Facility
Trailer Park subject to damage
SOURCE(S): Location: Figure 7: Moyer Creek High Risk Area #2 Herkimer County, New York
Map By: CMP MMI#: 5231-01 NYDOT: Emergency Transportation MXD: Y:\5231-01\GIS\Maps\High Risk Areas\Moyer High Risk #2.mxd Infrastructure Recovery 1st Version: XX/XX/201X 99 Realty Drive Cheshire, CT 06410 Revision: 3/19/2014 (203) 271-1773 Fax: (203) 272-9733 ³ Scale: 1 in = 125 ft www.miloneandmacbroom.com Moyer Creek continues to flow along the base of this plateau for approximately one-half mile (to STA 24+00), controlled by an aging stone and earthen levee along its right bank. This levee was reportedly built in the 1930s and is now extensively overgrown and in poor condition. The natural grade of the Moyer Creek floodplain (the village of Frankfort) to the east of this levee, however, is much lower in elevation than the channel bed elevation.
Streams and rivers will naturally flow to the lowest elevation when not anthropogenically influenced, indicating that this reach of Moyer Creek may have been channelized and relocated away from the village to its current location. The levees may have been constructed in an attempt to keep the creek from realigning itself toward the lower- elevation areas. During a flood, it is reported that floodwaters overtop the levees and flow eastward toward the lower elevations in the center of the village of Frankfort.
HEC-RAS modeling indicates that the existing levees are hydraulically capable of containing even the 500-year flood flows, but this assumes that the levees are properly maintained, maintain uniform elevations, and are continuous throughout the reach. One breach or discontinuity in a levee system can compromise the flood protection offered by the entire system. Limited field observation of the levee confirmed multiple breaches and discontinuities, which are likely to contribute to flooding in the area.
The levee system along Moyer Creek leads to the Swimming Road bridge crossing, which is subject to overtopping in extreme flood events. Hydraulic modeling indicates that flows greater than the 25-year event will cause the deck to be flooded and does not take into account debris or ice jamming. Flooding of this structure will cause backwaters upstream to rise until they may become capable of breaching the levees, even in properly maintained areas.
Alternative 2-1: Creation of Floodwater and Sediment Storage Area
The feasibility of storing floodwater within an area upstream of Route 5S (STA 63+00) was investigated, including construction of a low berm, excavation of a detention area, and a combination of both of these options. The option that included both the excavation of a detention area and the construction of a berm provided the largest storage potential. Allowing for one foot of freeboard, the total volume of storage during a 100-year frequency flood event would equal 116,250 cubic yards, or approximately three percent of the total storm runoff generated. A general "rule of thumb" for a feasible, cost-effective flood detention area is to store at least 10 percent of the runoff during the 100-year event. Given the limited detention capacity, this alternative is not considered to be feasible and is not recommended at this location. Calculations are included in Appendix D.
Alternative 2-2: Repair Levee and Replace Swimming Road Bridge
Because the floodplain of Moyer Creek is lower than the channel elevation, the natural tendency of the creek is to flood toward the village. A levee system was constructed along 2,300 linear feet of the channel to prevent that from happening. If properly sized
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 20 and maintained, a levee system can substantially mitigate flooding during severe events. Repair and reconstruction of the levee is necessary for long-term flood protection.
In addition to the repair and reconstruction of the levee system, replacement of the Swimming Road bridge should be investigated. The current bridge has a span of 50 feet, which hydraulic modeling predicts is capable of passing the 25-year flow event. Larger flows in Moyer Creek are predicted to cause backwater behind the bridge, which has the potential to overtop the levees. Increase of the bridge span to approximately 70 feet is recommended, to be confirmed with more detailed design analysis.
This alternative involves the following elements:
. Replace the Swimming Road bridge with a larger span structure capable of passing flows without creating an upstream backwater condition. . Repair the deteriorating stone and earthen levee along 2,300 linear feet of channel. . Continue to monitor the recent stabilization of the high bank failure and stabilization efforts.
Recommendations
It is likely that Moyer Creek would not remain in its current location if left to natural processes. Allowing the channel to relocate naturally may result in an alignment close to the existing South Litchfield Street (Route 171) corridor through the center of the village. Due to the heavy development in the area of the topographically logical route, it would not be practical to relocate the creek. Hence, continued use of levees to control flooding may be the only viable option.
Due to current regulations through the USACE and FEMA, isolated spot repairs of the existing levee system may not be possible without a full analysis, design, and reconstruction of the levee throughout its length. The cost for such a project is likely to be significant. Additionally, levee maintenance requires funding and staff, and even a properly maintained levee system can fail.
3.6 High-Risk Area #3 – Main Street Bridge, Canal Walls, and Existing Dam (STA 0+00 to STA 24+00)
Figure 8 is a location plan of High Risk Area #3. This area includes the lower portion of Moyer Creek, from STA 24+00 downstream to STA 0+00. Within this reach, Moyer Creek is prone to flooding, accumulation of ice, and accumulation of sediment and debris. The creek has steep slopes on the left bank and is confined for much of its length within a stone-lined channel, with discontinuous concrete structures lining the bottom of the channel.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 21 Railroad Abutments
Main Street Bridge- Hydraulic Constriction Flood Prone Dam
Flood Prone Buildings
SOURCE(S): Location: Figure 8: Moyer Creek High Risk Area #3 Herkimer County, New York
Map By: CMP MMI#: 5231-01 NYDOT: Emergency Transportation MXD: Y:\5231-01\GIS\Maps\High Risk Areas\Moyer High Risk #3.mxd Infrastructure Recovery 1st Version: 1/4/2014 99 Realty Drive Cheshire, CT 06410 Revision: 3/19/2014 (203) 271-1773 Fax: (203) 272-9733 ³ Scale: 1 in = 125 ft www.miloneandmacbroom.com Several floodprone buildings are located close to the channel on the right bank, between STA 19+50 and STA 16+50. The Main Street bridge (STA 16+00) acts as a hydraulic constriction. Downstream of Main Street are two additional structures located close to the channel on the right bank (STA 16+00 to STA 15+00), a dam (STA 13+00), and the abutments of a former railroad bridge (STA 11+00). The FEMA FIRM shows a significant constriction at the Main Street bridge, causing extensive ponding on both sides of Moyer Creek upstream of Main Street.
FEMA FIRMs indicate that, during the 100-year frequency flood event, water from Moyer Creek becomes ponded upstream of the Main Street bridge and floods homes and businesses along the southwest side of Main Street, extending northwest beyond Route 96 (Cemetery Street), southeast beyond Route 171 (South Litchfield Street), as well as onto Mill Street and other side streets in this area. According to the FEMA maps, floodwaters also overtop the banks on both sides of Moyer Creek downstream of Main Street, in the vicinity of the dam at STA 13+00.
A timber crib dam with cut stone training walls is located approximately 250 feet downstream of Main Street (STA 13+00). The dam does not impound substantial water and appears to be filled with sediment to its crest. During a flood event, backwater from the Mohawk River extends to the base of the dam. All development northeast of Industrial Drive, which is at a lower elevation than the predicted flood profiles of the Mohawk River, is also subject to these backwater effects and is located in the FEMA designated floodplain.
As shown in the Table 6, backwater from the Mohawk River reaches the base of the existing dam, but the influence from this backwater stops at the dam itself. Hydraulic modeling indicates that the dam only influences flood water elevations up to the downstream end of the Main Street bridge crossing. The model predicts that removal of the dam will not affect water surface elevations at the current Main Street bridge.
TABLE 6 Summary of Important Elevations
Mohawk 100-yr Backwater(From FEMA): 397.4 ft Mohawk 500-yr Backwater(From FEMA): 398.4 ft Timber Crib Dam, Base Elevation 392.0 ft Timber Crib Dam, Crest Elevation 400.0 ft Main Street Bridge, Low Chord Elevation 406.4 ft Main Street Bridge, High Chord Elevation 409.7 ft Main Street Bridge Deck Elevation 408.0 ft 100-yr WSEL Upstream of Main Street Bridge 413.6 ft 500-yr WSEL Upstream of Main Street Bridge 415.0 ft
Note: All elevations refer to NAVD88.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 23
Alternative 3-1: Replace Main Street Bridge With Larger Span
In order to address flooding in the Main Street area, replacement of the existing Main Street bridge with a larger span structure capable of passing a larger flood event without overtopping was evaluated. The work will involve disturbance of private properties and may involve utility impacts during the bridge replacement.
This alternative involves the following elements:
a) Acquire private property as necessary to facilitate removal of structures. b) Replace the Main Street bridge with a larger structure. c) Repair upstream banks where mortared stone walls are failing. d) Adopt and implement long-term sediment management plan.
Figure 9 shows the effects of replacing the Main Street bridge with an adequately sized crossing, which can reduce water surface elevations by approximately six feet. A bridge span of 70 feet was assumed for purposes of the model, in place of the existing 35-foot span bridge. Dam removal was also modeled and is shown in Figure 9; however, additional significant benefits would not be achieved.
FIGURE 9 Hydraulic Modeling of Dam Removal and Main Street Bridge Replacement Water Surface Elevations for 100-Year Flow
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 24
The banks upstream of the Main Street bridge will also require stabilization. Mortared stone walls located approximately 400 feet upstream of Main Street (STA 20+00) support the banks but have begun to fail. These 20-foot high walls were reportedly constructed as part of a canal project but, as they deteriorate, they have begun to expose the vulnerable soils behind them to erosion, generating sediment that can lead to aggradation of the channel near the floodprone areas.
Sediment aggradation is also an issue at the Main Street bridge. Hydraulic modeling was performed under current conditions, indicating that the bridge is severely undersized without the effects of sediment aggradation. The accumulation of additional sediment causes the waterway opening to be reduced and flooding to be worse. Therefore, in addition to bridge replacement, implementation of a sediment management plan is also recommended to define how and when to remove sediment from the area.
Alternative 3-2: Implement Sediment Management Plan
Dredging (specifically lowering) Moyer Creek was evaluated. Such action will further isolate the stream from its natural floodplain, disrupt sediment transport, potentially cause upstream bank/channel scour, and encourage additional downstream sediment deposition. Improperly dredged stream channels often show signs of severe instability, which can cause larger problems after the work is complete. Such a condition is likely to exacerbate flooding on a long-term basis.
Because no approach can fully mitigate sediment accumulation due to the natural gradient of the creek, a sediment management program should be considered. This would involve the development of standards to delineate how, when, and to what dimensions sediment excavation should be performed. It will also require the proper regulatory approval, as well as budgetary considerations to allow the work to be funded on an ongoing or as-needed basis as prescribed by the standards to be developed.
The need for excavation of sediment from the stream channel on Moyer Creek can be reduced by decreasing the sediment load at its sources (i.e., by repairing bank failures and headcuts and reducing erosion) and by improving sediment transport with adequately sized stream crossings. Some sediment is likely to continue to be transported downstream regardless of what actions are taken to control sediment in the upper reaches. These suspended materials are prone to depositing in the lower reaches, thus reducing channel capacity and contributing to flooding.
Dredging is often the first response to sediment deposition and clogging of the stream channel or bridge openings; however, over-widening or over-deepening through dredging can initiate headcutting, foster poor sediment transport, result in low habitat quality, and not necessarily provide significant flood mitigation. Dredging can further isolate a stream from its natural floodplain, disrupt sediment transport, expose erodible sediments, cause upstream bank/channel scour, and encourage additional downstream sediment
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 25 deposition. Improperly dredged stream channels often show signs of severe instability, which can cause larger problems after the work is complete. Such a condition is likely to exacerbate flooding on a long-term basis.
A sediment management program should involve the development of standards to delineate how, when, and to what dimensions sediment excavation should be performed. It will also require the proper regulatory approval, as well as budgetary considerations to allow the work to be funded on an ongoing or as-needed basis as prescribed by the standards to be developed.
Conditions in which active sediment management should be considered include:
. Situations where the channel is confined, without space in which to laterally migrate . For the purpose of infrastructure protection . At bridge openings where hydraulic capacity has been compromised . In reaches with low habitat value
In cases where sediment management of the stream channel is necessary, a methodology should be developed that would allow for proper channel sizing and slope. The following guidelines are provided:
1. Maintain the original channel slope and do not overly deepen or widen the channel. Excavation should not extend beyond the channel's estimated bankfull width unless it is to match an even wider natural channel. Estimated bankfull widths on Moyer Creek are provided in Table 1 of this report.
2. Sediment management should be limited in volume to either a single flood's deposition or to the watershed's annual sediment yield in order to preclude downstream bed degradation from lack of sediment. Annual sediment yields vary, but one approach is to use a regional average of 50 cubic yards per square mile per year unless a detailed study is made. The estimated annual sediment yield of Moyer Creek is 995 cubic yards.
3. Excavation of fine-grain sediment releases turbidity. Best available practices should be followed to control sedimentation and erosion.
4. Sediment excavation requires regulatory permits. Prior to initiation of any in-stream activities, NYSDEC should be contacted, and appropriate local, state, and federal permitting should be obtained.
5. Disposal of excavated sediments should always occur outside of the floodplain. If such materials are placed on the adjacent bank, they will be vulnerable to remobilization and redeposition during the next large storm event.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 26 6. No sediment excavation should be undertaken in areas where rare or endangered species are located.
Recommendations
Replacement of the Main Street bridge with a hydraulically adequate structure is recommended in combination with bank repair to mitigate flooding of the area for most severe flood events modeled. This, combined with maintenance of accumulated sediment, can be an effective flood mitigation solution for this reach.
4.0 RECOMMENDATIONS
1. Realign Route 171and Replace Undersized Bridges and Culvert (STA 80+00 to STA 280+00) – Replacement of undersized bridges that cross Moyer Creek along Route 171 is recommended as a long-term plan to better protect the roads and bridges from flood damage. Replacement of all of the bridges may be too costly to undertake at once; however, the state may wish to pursue a replacement program over time to address bridge spans and alignment issues as these structures are scheduled for rehabilitation or replacement.
2. Repair Levee System Upstream of Swimming Road (STA 47+00 to STA 52+00) – A levee system upstream of Swimming Road appears to be adequately sized to convey severe floods. However, a lack of maintenance of the structure has caused breaches and inconsistencies that compromise the ability of the system to mitigate flooding through the center of Frankfort. Design and reconstruction are recommended to prevent floodwaters from inundating large areas within the village of Frankfort.
3. Monitor Stream Near Repaired High Bank Failure Near Station 49+00 – The stream adjacent to the recently repaired high bank failure is overly wide. Monitoring of this site is recommended to ensure that aggradation of sediment does not compromise the function of the adjacent levee.
4. Replace Swimming Road Bridge with a Larger Span Structure (STA 34+00) – After repair of the levees is undertaken, backwater from the Swimming Road bridge may cause even properly sized and maintained levees to overtop. It is recommended that the Swimming Road bridge be replaced to prevent this from happening.
5. Replace Main Street Bridge with a Larger Span Structure (STA 16+00) – The primary driver for flooding in the Main Street area is the severely undersized bridge carrying Main Street across Moyer Creek. This bridge should be slated for replacement with a hydraulically adequate structure as soon as funding allows.
6. Adopt Sediment Management Standards – Large volumes of coarse-grained sediments will continue to be transported into Moyer Creek during high flow events regardless of what actions are taken to control sediments in the upper reaches and
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 27 tributaries. These sediments will be deposited in the lower reaches, reducing channel capacity and contributing to flooding. When excavation of depositional areas is necessary, it should be undertaken in a manner that maintains channel stability, avoiding over-widening and/or over-deepening the channel. Development of sediment management standards is recommended to provide guidance to contractors and local municipal and county public works departments on how to maintain proper channel sizing and slope as well as the application of best practices.
7. Monitor Minor Bank Failures and Erosion – Several areas of eroding banks, minor bank failures, and slumping hill slopes were observed along Moyer Creek. These are of low to moderate severity, appear to be relatively stable, and at the time of the field visits were not contributing a large amount of sediment to the channel. It is recommended that these sites be monitored periodically and stabilized as necessary.
8. Acquisition of Floodprone Properties – Undertaking flood mitigation alternatives that reduce the extent and severity of flooding is generally preferable to property acquisition. However, it is recognized that flood mitigation initiatives can be costly and may take years or even decades to implement. Where properties are located within the FEMA designated flood zone and are repeatedly subject to flooding damages, strategic acquisition, either through a FEMA buyout or other governmental programs, may be a viable alternative. There are a number of grant programs that make funding available for property acquisition. Such properties could be converted to passive, non-intensive land uses.
9. Evaluate Floodplain Regulations – A critical evaluation of existing floodplain law and policies should be undertaken to evaluate the effectiveness of current practices and requirements. Identification of a floodplain coordinator and development of a detailed site plan review process for all proposed development within the floodplain would provide a mechanism to quantify floodplain impacts and ascertain appropriate mitigation measures.
10. Install and Monitor a Stream Gauge – There is currently no stream gauge on Moyer Creek, making statistical analysis difficult. Installation of a gauge would inform future analysis of the brook and is recommended.
11. Develop Design Standards – There is currently no requirement to design stream crossings to certain capacity standards. For critical crossings such as major roadways or crossings that provide sole ingress/egress, design to the 50- or 100-year storm event may be appropriate. Less critical crossings in flat areas may be sufficient to pass only the 10-year event. Crossings should always be designed in a manner that does not cause flooding. When a structure that is damaged or destroyed is replaced with a structure of the same size, type, and design, it is reasonable to expect that the new structure will be at risk for future damage as well. Development of design standards is recommended for all new and replacement structures.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 28 The above recommendations are graphically depicted on the following pages. Table 7 provides an estimated cost range for key recommendations.
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 29
TABLE 7 Cost Range of Recommended Actions
Approximate Cost Range Moyer Creek Recommendations < $100k $100k-$500k $500k-$1M $1M-$5M >$5M Realign Route 171 and Replace Undersized Bridges and Culvert X Replace Main Street Bridge with a Larger Span Structure X Repair Levee Upstream of Swimming Road X Replace Swimming Road Bridge with a Larger Span Structure X Install and Monitor a Stream Gauge X
WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK APRIL 2014 PAGE 30 WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK High‐Risk Area #1 –Road Crossings in Frankfort Gorge
Site Description: Along Frankfort Gorge, Route 171 crosses over Moyer Creek a total of seven times with a distance of 3.6 miles. Many of the bridges have poor alignments with the creek and most of the bridges do not span the bankfull width therefore create hydraulic constrictions during peak flows. The undersized bridges along Route 171 include: East of Ball Road (340+50), West of Furnace Road (266+00), East of Furnace Road (235+50), D/S of Parking Area (148+00), and West of Brice Road (134+00).
Recommended Alternative: • Replace undersized bridge crossings as funding becomes available. • Ensure new bridge crossings are adequately sized to span the regional bankfull width, and to safely pass severe flood events with the freeboard required by State of NY design standards. • Consider alignment of bridges to a more perpendicular angle of approach.
BENEFITS Improved safety Reduction in debris jams Improved hydraulic capacity Reduced flood hazard Improved ecological connectivity WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK
High‐Risk Area #2 –High Bank Failure And Levees
Site Description: This high risk area runs from STA 57+00 to 24+00, confined by steep slopes on the left bank and a discontinuous stone wall and earthen levee on the right. Included in this area are Edgebrook Estates and a Senior Living Facility, both which have experienced flood damage, and a large bank failure.
Recommended Alternative: • Repair/reconstruct 2,300 linear feet of existing levee to restore the flood mitigation ability of the levee system. • Remove and replace Swimming Road bridge with a larger structure capable of passing severe flood flows without hydraulic restriction.
BENEFITS Improved safety Reduction in debris jams Improved hydraulic capacity Reduced flood hazard WATER BASIN ASSESSMENT AND FLOOD HAZARD MITIGATION ALTERNATIVES MOYER CREEK, HERKIMER COUNTY, NEW YORK
High‐Risk Area #3 –Main Street Bridge, Canal Walls, and Dam
Site Description: This high risk area begins at STA 24+00 downstream to STA 0+00. Within this area, Moyer Creek is prone to flooding, accumulation of ice, and accumulation of sediment and debris. The creek has steep slopes on the left bank, and is confined for much of its length within a stone‐lined channel, with discontinuous concrete structures lining the bottom of the channel.
Recommended Alternative: • Remove and replace Main Street bridge with a larger structure capable of passing severe flood flows without hydraulic restriction. • Develop dredging standards and implement long‐term sediment management plan.
BENEFITS Improved safety Reduction in debris jams Improved hydraulic capacity Reduced flood hazard Improved ecological connectivity
APPENDIX A
Summary of Data and Reports Collected
Emergency Transportation Infrastructure Recovery, Waterbasin Assessment NYSDOT PIN # 2FOI.02.301 Herkimer, Oneida, and Montgomery Counties, New York MMI Proj. #5231‐01 December 10, 2013 ATTACHMENT A: DATA INVENTORY
Year Data Type Document Title Author 2013 Presentation Flood Control Study for Fulmer Creek Schnabel Engineering 2012 Map Sauquoit Creek Watershed/Floodplain Map Herkimer‐Oneida Counties Comprehensive Planning Program 2011 Report Oriskany Creek Conceptual Plan and Feasibility Study for Watershed Project Oneida County SWCD 2009 Presentation Ice Jam History and Mitigation Efforts National Weather Service, Albay NY 2007 Report Cultural Resources Investigations of Fulmer, Moyer, and Steele Flood Control Projects United States Army Corps of Engineers (USACE) 2006 Report Riverine High Water Mark Collection, Unnamed Storm Federal Emergency Management Agency (FEMA) 2005 Report Fulmer Creek Flood Damage Control Feasibility Study United States Army Corps of Engineers (USACE) 2005 Report Steele Creek Flood Damage Control Feasibility Study United States Army Corps of Engineers (USACE) 2004 Report Fulmer Creek Basin Flood Hazard Mitigation Plan Herkimer‐Oneida Counties Comprehensive Planning Program 2004 Report Moyer Creek Basin Flood Hazard Mitigation Plan Herkimer‐Oneida Counties Comprehensive Planning Program 2004 Report Steele Creek Basin Flood Hazard Mitigation Plan Herkimer‐Oneida Counties Comprehensive Planning Program 2003 Report Fulmer, Moyer, Steele Creek ‐ Stream Bank Erosion Inventory Herkimer‐Oneida Counties Comprehensive Planning Program 1997 Report Sauquoit Creek Watershed Management Strategy Herkimer‐Oneida Counties Comprehensive Planning Program 2011 Report Flood Insurance Study (FIS), Herkimer County Federal Emergency Management Agency (FEMA) 2011 Report Flood Insurance Study (FIS), Montgomery County Federal Emergency Management Agency (FEMA) 2013 Report Flood Insurance Study (FIS), Oneida County Federal Emergency Management Agency (FEMA) 2010 Report Bridge Inspection Summaries, Multiple Bridges National Bridge Inventory (NBI) 2002 Hydraulic Models Flood Study Data Description and Assembly ‐ Rain CDROM New York Department of Enviromental Conservation (NYDEC) 2013 Data June/July 2013 ‐ Post‐Flood Stream Assessment New York State Department of Transportation (NYSDOT) 2013 GIS Data LiDAR Topography, Street Mapping, Parcel Data, Utility Info, Watersheds Herkimer‐Oneida Counties Comprehensive Planning Program 2013 GIS Data Aerial Orthographic Imagery, Basemaps Microsoft Bing, Google Maps, ESRI 2011 GIS Data FEMA DFIRM Layers Federal Emergency Management Agency (FEMA) 2013 Data Watershed Delineation and Regression Calculation US Geological Survey (USGS) ‐ Streamstats Program
APPENDIX B
Field Data Collection Forms
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Sources: Esri, DeLorme, NAVTEQ, TomTom, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance App B-1 Survey, Esri Japan, METI, Esri China (Hong Kong), swisstopo, and the GIS User Community, Copyright:© 2013 Esri, DeLorme, NAVTEQ, TomTom 3 3 7 m 9 - o c 0 2 . 7 1 2 4 m
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Sources: Esri, DeLorme, NAVTEQ, TomTom, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance App B-2 Survey, Esri Japan, METI, Esri China (Hong Kong), swisstopo, and the GIS User Community, Copyright:© 2013 Esri, DeLorme, NAVTEQ, TomTom MMI Project #5231-01 Phase I River Assessment Reach Data
River ______Reach ______U/S Station ______D/S Station ______Inspectors ______Date ______Weather ______
Photo Log ______
A) Channel Dimensions: Bankfull Width (ft) ______Depth (ft) ______
Watershed area at D/S end of reach (mi2) ______
B) Bed Material: Bedrock Boulders Cobble Gravel Sand Clay Concrete Debris Riprap
Notes: ______
C) Bed Stability: Aggradation Degradation Stable Note: ______
D) Gradient: Flat Medium Steep Note: ______
E) Banks: Natural Channelized Note: ______
F) Channel Type: Incised Colluvial Alluvial Bedrock Note: ______
G) Structures: Dam Levee Retaining Wall Note: ______
H) Sediment Sources: ______
I) Storm Damage Observations: ______
______
J) Vulnerabilities: Riverbank Development Floodplain Development Road Trail Railroad
Utility Bridge Culvert Retaining Wall Ball field Notes: ______
K) Bridges: Structure # ______Inspection Report? Y N Date ______
Notes: ______
Record span measurements if not in inspection report: ______
Damage, scour, debris: ______
L) Culverts: complete culvert inspection where necessary. Size: ______
Type: ______Notes: ______
______Phase II River Assessment Reach Data
River ______Reach ______Road ______Station ______Inspector ______Date ______Town ______County ______Identification Number ______GPS # ______Photo # ______
A) River Reach ID ______Drainage Area, sm ______D/S Boundary ______, U/S Boundary ______D/S STA ______, U/S STA ______D/S Coordinates ______, U/S Coordinates ______
B) Valley Bottom Data: Valley Type Confined Semiconfined Unconfined (Circle one) >80% L 20-80% <20%
Valley Relief <20' 20-100' >100
Floodplain Width <2 Wb 2-10 Wb >10 Wb ______Left Side Right Side Natural floodplain ______% ______% Developed floodplain ______% ______% Terrace ______% ______%
Floodplain Land Use ______
C) Pattern: Straight Sinuous Meanders Highly Meandering Braided Wandering Irregular S=1-1.05 S=1.05 – 1.25 S=1.25 – 2.0 S>2.0
D) Channel Profile Form: (Percent by Class in Reach) Cascades ______Alluvial ______Channel Transport Steep Step/Pool ______Semi Alluvial ______Sed. Source Area Fast Rapids ______Non Alluvial ______Eroding Tranquil Run ______Channelized ______Neutral Pool & Riffle ______Incised ______Depositional Slow Run ______Headcuts ______
E) Channel Dimensions (FT): Bankfull Actual Top of Bank Regional HGR Width ______Depth ______Inner Channel Base Width ______W/D Ratio ______
F) Hydraulic Regime: Mean Bed Profile Slope ______Ft/Ft Observed Mean Velocity ______FPS
G) Bed Controls: Bedrock Weathered Bedrock Dam Static Armor Cohesive Substrate Bridge Boulders Dynamic Armor Culvert Debris Riprap Utility Pipe/Casing Overall Stability ______
H) Bed Material: Bedrock ______Sand ______Riprap ______Boulders ______Silt and Clay ______Concrete ______D50 ______Cobble and Boulder ______Glacial Till ______Gravel and Cobble ______Organic ______Sand and Gravel ______
I) Flood Hazards: Developed Floodplains Bank Erosion Buildings Aggradation Utilities Sediment Sources Hyd. Structures Widening phase i river assessment - reach data form.docx Bridge Waterway Inspection Summary
River ______Reach ______Road ______Station ______
Inspector ______Date ______NBIS Bridge Number ______
NBIS Structure Rating ______Year Built ______
Bridge Size & Type ______Skew Angle ______
Waterway Width (ft) ______Waterway Height (ft) ______
Abutment Type (circle) Vertical Spill through Wingwalls
Abutment Location (circle) In channel At bank Set back
Bridge Piers ______Pier Shape ______
Abutment Material ______Pier Material ______
Spans % Bankfull Width ______Allowance Head (ft) ______
Approach Floodplain Width ______Approach Channel Bankfull Width ______
Tailwater Flood Depth or Elevation ______Flood Headloss, ft ______
Left Abutment Piers Right Abutment Bed Materials, D50 Footing Exposure Pile Exposure Local Scour Depth Skew Angle Bank Erosion Countermeasures Condition High Water Marks Debris
Bed Slope Low Medium Steep Vertical Channel Stability Stable Aggrading Degrading Observed Flow Condition Ponded Flow Rapid Turbulent Lateral Channel Stability ______Fish Passage ______Upstream Headwater Control ______
Project Information Particle Distribution (%) Project Name silt/clay Project Number sand Stream / Station gravel Town, State cobble Sample Date boulder Sampled By bedrock Sample Method Wolman Pebble Count
Sample Site Descriptions by Observations Particle Sizes (mm) Channel type D16 Misc. Notes D35 D50 D84 D95 (Bunte and Abt, 2001) Size Limits (mm) Percent Cumulative Particle Name lower upper Tally Count Passing % Finer F-T Particle Sizes (mm) silt/clay 0 0.063 0.0 0.0 F-T n-value 0.5 very fine sand 0.063 0.125 0.0 0.0 D16 fine sand 0.125 0.250 0.0 0.0 D5 medium sand 0.250 0.500 0.0 0.0 (Fuller and Thompson, 1907) coarse sand 0.500 1 0.0 0.0 very coarse sand 1 2 0.0 0.0 D (mm) of the largest very fine gravel 2 4 0.0 0.0 mobile particles on bar fine gravel 4 5.7 0.0 0.0 fine gravel 5.7 8 0.0 0.0 medium gravel 8 11.3 0.0 0.0 medium gravel 11.3 16 0.0 0.0 coarse gravel 16 22.6 0.0 0.0 coarse gravel 22.6 32 0.0 0.0 Mean very coarse gravel 32 45 0.0 0.0 very coarse gravel 45 60 0.0 0.0 small cobble 60 90 0.0 0.0 Riffle Stability Index (%) medium cobble 90 128 0.0 0.0 large cobble 128 180 0.0 0.0 (Kappesser, 2002) very large cobble 180 256 0.0 0.0 small boulder 256 362 0.0 0.0 Notes small boulder 362 512 0.0 0.0 medium boulder 512 1024 0.0 0.0 large boulder 1024 2048 0.0 0.0 very large boulder 2048 4096 0.0 0.0 bedrock 4096 - 0.0 0.0 (Wenthworth, 1922) Total 0 0.0 -
Particle Size Histogram Gradation Curve
1 100 sand gravel cobble boulder 0.9 90
0.8 80 0.7 70 0.6 60 0.5 50 0.4 40
0.3 Percent Finer 30 20
Percent by Percent by Size (%) 0.2 0.1 10 0 0 1 2 4 8
16 32 45 60 90 0 1 10 100 1000 10000 5.7 128 180 256 362 512 11.3 22.6 1024 2048 4096 0.125 0.250 0.500 Particle size (mm) Particle size (mm)
APPENDIX C
Moyer Creek Photo Log
Moyer Creek MMI# 5231-01 99 Realty Drive Photo Log NYDOT Cheshire, Connecticut 06410 January 2014 (203 271-1773
PHOTO NO.:
1
DESCRIPTION:
This represents the high relief in the upper reaches of Moyer as well as deteriorated grade control structures. Photo location is approximate at station 190+00.
PHOTO NO.:
2
DESCRIPTION:
At station 150+50 this tributary flows through a culvert beneath Rt 171 before entering Moyer Creek. This crossing becomes filled with debris during storm events causing flows to overtop the road.
Page 1 of 4 Moyer Creek MMI# 5231-01 99 Realty Drive Photo Log NYDOT Cheshire, Connecticut 06410 January 2014 (203 271-1773
PHOTO NO.:
3
DESCRIPTION:
An example of the many bridges along the upper reaches of Moyer that constrict flows due to their alignment. Note upstream of the bridge the river does a sweeping turn before passing beneath Rt 171. This bridge is located at station 145+00.
PHOTO NO.:
4
DESCRIPTION:
Beginning at station 51+00, this high bank failure is a major source of sediment to downstream and a threat to undermining of the athletic fields at the top of the bank. To the left of the photo is the trailer home park that has been subject to major flood damage.
Page 2 of 4 Moyer Creek MMI# 5231-01 99 Realty Drive Photo Log NYDOT Cheshire, Connecticut 06410 January 2014 (203 271-1773
PHOTO NO.:
5
DESCRIPTION:
This stone reventment wall has been constructed to deter flows from further undermining the head cut at stations 51+00 through 46+00.
PHOTO NO.:
6
DESCRIPTION:
Viewing from station 20+00, this is a deteriorated aquaduct that was part of the Old Erie Canal. Downstream is the Main Street bridge which causes hydraulic constriction and ponding in this section of Moyer Creek.
Page 3 of 4 Moyer Creek MMI# 5231-01 99 Realty Drive Photo Log NYDOT Cheshire, Connecticut 06410 January 2014 (203 271-1773
PHOTO NO.:
7
DESCRIPTION:
Looking upstream from the Main Street bridge at station 16+00, the watercourse is confined by stone-lined channels before and after crossing Main Street.
PHOTO NO.:
8
DESCRIPTION:
Looking at the dam at station 13+00 with the Main Street bridge just upstream.
Page 4 of 4
APPENDIX D
Detention Basin Computations
Moyer Creek Stage Storage Analysis Computed By:_JCS_2/5/14 Checked By:______MMI# 5231‐01
Alt. 1 - Berm and Grading Stage vs. Storage
Incremental Distance Below Elevation Area Incremental Volume Incremental Volume Volume with 1 yd Spillway (ft) (ft.) (s.f.) (c.f.) (c.y.) (c.y.) 0 472 643,851 626,337 23,198 0 1 471 608,822 590,376 21,866 21,866 2 470 571,930 548,434 20,312 20,312 3 469 524,938 498,777 18,473 18,473 4 468 472,616 455,101 16,856 16,856 5 467 437,585 411,354 15,235 15,235 6 466 385,122 348,466 12,906 12,906 7 465 311,809 286,231 10,601 10,601 8 464 260,652 0 0 0 Total: 3,765,074 139,447 116,250