Board of Trustees

MEETING NOTICE Village of Scarsdale A Work Session of the Scarsdale Village Board of Trustees is scheduled for 6:00 PM on Tuesday, December 5, 2023. The meeting will be held in the 3rd Floor Meeting Room in Village Hall. Members of the public wishing to participate in the meeting remotely can do so via online link at https://zoom.us/j/93183703358, or call into the meeting using 1-929-436-2866 and entering the Meeting ID 931 8370 3358.* Upon concluding discussion on item #1 on the agenda, it is anticipated that the Village Board will act upon a motion to convene in Executive Session for item #2 below. AGENDA 1. Stormwater Improvements 2. Executive Session on Personnel Matters CS: 11-30-23 E-MAIL: Journal News (Lohud) Scarsdale 10583 Scarsdale Hamlet Hub Scarsdale Inquirer The Daily Scarsdale cc: Lobby Bulletin Board *For a brief Zoom tutorial or to troubleshoot a problem, see here: https://support.zoom.us/hc/en- us/articles/205566129-Raise-Hand-In-Webinar. For other user questions, please visit the Zoom Help Center: https://support.z-oom.us/hc/en-us. Village of Scarsdale Memorandum Department of Public Works To: Robert Cole, Village Manager From: Jeffrey C. Coleman, PE, Superintendent of Public Works Date: December 1, 2021 Re: Tropical Storm IDA and July 8th Storm Events Tropical Storm Ida impacted the region on the evening of September 1, 2021. The National Weather Service reported that the storm dropped over 8 inches of rain in a 24-hour period in Scarsdale. Just as important as the total rainfall, the intensity of the rain event dictates where and to what degree flooding occurs in certain areas of the Village. As a point of reference, the 100-year storm, which forms the basis for much of the Federal Emergency Management Agency flood mapping is based on a storm with a magnitude of 9 inches of rain over a 24-hour period. On July 8, 2021, a rainstorm also impacted the Village. This storm, while not as long in duration, provided 3” to 4” of rain between 15:00 and 18:00. This storm event resulted in impacts to multiple areas of the Village. The Department was working to address issues that surfaced during this event when Tropical Storm Ida impacted the region on September 1st. For the purposes of this report, the observations made by staff and residents during this event are also included in this report. Emergency Response During the evening of September 1, 2021, Police, Fire, Public Works and SVAC worked to rescue stranded motorists and property owners and remove them to safety in the dark of night. By daylight, multiple cars were stranded along village roadways and abutting New York State and Westchester County highways (Bronx River Parkway and Hutchinson River Parkway). The storm had caused inundation to the point where multiple roadways in the Village were temporarily impassable. Once the water began to recede on September 2, 2021, multiple vehicles were found abandoned along these roadways and had to be towed. Village Infrastructure Impacts The following Village infrastructure received damage due to flooding. Public Safety Building - Water damage to the contents and finishes in the basement level of this building requiring remediation. Restoration work to this building is partially complete.  Page 2 of 8 Crossway Firehouse (Station 3) – The basement area of this building received stormwater resulting in significant damage. Restoration work to the damaged area is partially complete. Central Garage - The stormdrain system at the Central Garage was overwhelmed resulting in inundation in front of the building to the point where water rose approximately ½ way up the fuel pumps. Stormwater flowed though the Central Garage building as well as the adjacent Forestry/Board of Education Maintenance building. Clean up and restoration work is complete. Facilities Maintenance building - located at the same complex as the Central Garage, this building is partially below grade. This area, including the building, flooded due to overland flow and the existing storm drain system being over capacity. Clean up and restoration work is complete. Private property and roadway inundation. As previously indicated, much of the Village was inundated with surface water during/following the storm event and mirrored (to a large extent) the FEMA flood mapping prepared for the Village. However there were several areas throughout the village which were flooded that did not show up as flood areas on the FEMA mapping. This included (but is not limited to) Spier Road, Griffen Avenue, Palmer Avenue, Paddington at Fox Meadow Road, White Birch Lane, Greendale Road, areas abutting the Hutchinson River, Ferncliff Road, Richbell Road, Birch Lane, and Circle Road. Homes flooded by this event were largely due to either the local storm drain system being overwhelmed (more water than the system was able to convey), natural watercourses being overwhelmed (more water than the stream bed can convey), or sanitary sewer back up. Sanitary sewer backups were caused by either infiltration, or direct inflow. As was experienced by this area during the flooding in 2007, multiple property owners indicated that they resolved basement flooding in their home by discharging water from their flooded basement into the sanitary sewer. This action resulted in flooding the sanitary downstream, which, in turn, resulted in backups. It can reasonably be surmised that this also occurred during this event. Specific areas of response/recovery The following are locations that required response and recovery efforts by the Department. Olmstead Road - The most significant culvert damage occurred at Olmstead Road. The upstream end of the culvert was undermined during the storm event resulting in the culvert sinking approximately 1 foot. This reduced the culvert capacity in half. With the capacity reduced, flood waters overtopped the road, destroying the culvert and its surrounds. The Facilities Maintenance Division reconstructed the culvert in-situ, and restored the surrounding area. This work was completed this month.  Page 3 of 8 View looking south at Olmsted Road showing undermined and sunken section of the box culvert. Spier Road – the culvert crossing beneath Spier Road at 111 Spier Road was overwhelmed resulting in the road being overtopped and washing out the guiderail, curbing and roadway edge. Facilities Maintenance has since rebuilt the guiderail, curb and as restored the roadway edge. Spier Road washout  Page 4 of 8 Church Lane South – It was discovered that the stormdrain located on Church Lane South was not properly draining. Based on video inspection, it has been determined that the drain line is failing to the point where it requires replacement. This drain runs through a prescriptive easement through back yards that will require the cooperation of the property owners and restoration of the areas post construction. This work has not yet begun. Rugby Road – This area experienced significant flooding during successive events. A storm drain runs behind the homes on the north side of Rugby Road and connects to a 42” concrete storm drain running parallel to the Post Road. This drain begins at Oxford and extends to the open watercourse along the East side of Post Road south of Fenimore Road. During the storm event, the 42” drain was observed as flowing full. This limited the ability for the Rugby Road drain to flow/outlet freely by creating a significant backwater condition. However, the Rugby Road drain was cleaned and found to have roots and debris (a 5 gallon jug of motor oil). Given the condition of the pipe, this section will be lined by the village’s contractor. To effectuate the work, Facilities Maintenance Department has constructed a manhole over the blind connection between the 42” drain and the Rugby Road drain. Sheldrake Road – The road was overtopped near 34 Sheldrake Road. A preliminary investigation has indicated that the drainage system and the system to the south that runs beneath the properties along the east side of Colby Lane requires cleaning. Following cleaning, this corrugated metal pipe will be evaluated as to soundness. Brite Avenue – Flooding in several areas of Brite Avenue due to the existing storm drain system being overwhelmed. This includes Chesterfield Road and Donellen Road. Along Brite Avenue at Donellen Road, a sinkhole has developed. Upon video inspection, damage to both the stormdrain and sanitary sewer was discovered. The Department is working to line the damaged section of sanitary sewer. A contractor will be engaged to replace the damaged section of the stormdrain. Flooding along Brite Avenue adjacent to the Brite Avenue tennis courts.  Page 5 of 8 Oxford Road – Oxford Road was overtopped and impassable due to the existing storm drain being overwhelmed. The areas between Oxford Road and Mamaroneck Road, paralleling the Post Road was inundated. Oxford Road flooding, September 2, 2021. Sheldrake River Basin – This area of the village includes Oneida Road, Cayuga Road, Leatherstocking Lane, Canterbury Road, Catherine Road, Brookby Road. These areas experienced significant flooding. This includes Scarsdale Medical Building as well as multiple properties in this area. Garden Road, Cushman Road and Sheldrake Road at Willow Lane – This area represents the upper reaches of the Sheldrake River Basin. Stormwater in this area overwhelmed the storm drain system and culvers resulting in overland flow. Griffen Avenue – The culvert adjacent to 237 Griffen Avenue was overwhelmed this resulted in significant scour and washout, closing Griffen Avenue to traffic following the storm. Department forces removed the debris, backfilled the scoured area, and re-opened the road to traffic. It has been determined that a downstream condition on private property in the Town of Mamaroneck may have contributed to the backwater condition which was created during the night of the storm. Engineering Department staff have met with Town officials to review the conditions occurring on private property in an attempt to reduce the likelihood of reoccurrence.  Page 6 of 8 Griffen Avenue flood damage (adjacent to 237). Sherbrooke Road – The drainage system, and natural watercourses along the dead end section of Sherbrook Road were overwhelmed resulting in the road becoming inundated. Pavement at various roadways – Multiple areas throughout the village suffered pavement delamination, curbline scour and heave. The result is an overall reduction in the life expectancy of pavement in those areas that were inundated. It will manifest itself as an increase in potholes during the upcoming winter months. Debris Removal Debris collection and disposal was a significant part of the Department’s recovery efforts. Beginning almost immediately following the end of the storm, flood damaged debris began appearing in the public right of way as residents removed debris from their homes. In an effort to manage the debris volume/mix, construction and demolition debris was not accepted by the Department. Close coordination with the Westchester County Department of Environmental Facilities (WCDEF) enabled DPW staff to collect debris into the evening on multiple days and on two consecutive Saturday’s. WCDEF operates the County transfer stations which accept municipally collected debris. The operation was successfully managed such that a debris staging area was not necessary. All debris collected at the curb was transported and disposed of at one of the County transfer stations. This operation resulted in the collection of approximately 425 tons of debris. By comparison, in a typical month, the Department collects approximately 600 tons of garbage and trash.  Page 7 of 8 Cayuga Road debris placed for collection. Watercourse Inspection Post storm event, the Engineering Department inspected private watercourses in several areas of the Village. This included the following areas Brookby Road, Scarsdale Medical building, Sherbrooke Road, Richbell Road, Cayuga Road, Catherine Road, Brookby Road. Overall it was found that waterways were generally clear of debris. However, 23 property owners were sent letters advising them to remediate and remove obstructions in accordance with Village Code Chapter 302 for watercourse management. The Engineering Department has also fielded several calls and advised multiple property owners living in the flood zone, regarding private flood mitigation improvements that they may undertake. Engineering Department will continue to follow up with the affected properties. Next Steps The following next steps are recommended. 1. The Department will continue its investigative efforts to inspect, clean and repair the Village stormdrain system to ensure that the system is operating with its maximum carrying capacity. The areas of the system that were suspected of having obstructions have been video inspected by the Village’s contractor. Most field work has been completed. The videos are to be  Page 8 of 8 processed and reviewed by the Department to determine the appropriate course of action in each instance. 2. Repair locations identified through the investigative efforts thus far. In some cases this involves pipe lining, while in others it involves construction within easements on private property. 3. Continue to inspect non-village watercourses and work with property owners to clean and remove obstructions. 4. In 2009 the engineering firm of Dvirka and Bartilucci completed the Village’s comprehensive stormwater management plan. This effort identified several projects to reduce the occurrence of flooding in the Village. Several of the projects have been completed, including the South Fox Meadow drainage improvements, George Field Park, etc. Some projects, such as the Hutchinson River drainage project, are underway, but have a long lead time. Other projects have proved to be either infeasible or not cost effective. Based on a review of the study through the lens of the experiences during Tropical Storm Ida, it is worthwhile to revisit each of the previously proposed projects to determine their appropriateness. Further, it is recommended that the areas not subject to the original study, but identified as candidates for some type of improvement, be evaluated. (It is however, important to recognize that in many cases, it is unlikely that the Village can construct improvements that are cost effective and provide meaningful improvement.) The Department has secured a proposal from STV Incorporated to perform an evaluation of the recommendations of the 2009 study, provide a preliminary evaluation of several areas that were identified as having some potential for improvement, and offer recommendations for further detailed study and design. This would be the first step in identifying and advancing the next series of improvements and form the basis for future grant applications. The cost of the study is $27,810 and funds are available in account H-8597-965 2016-014. STV was chosen as they are uniquely qualified to perform this project with the least amount of background work. The project lead performed much of the work on prior stormwater management projects with a prior engineering firm. 5. Evaluate the need for changes to the following sections of the Village Code: Chapter 167 - Flood Damage Prevention, Chapter 254 - Stormwater Management, and Chapter 302 - Diversion of Watercourses. 6. Continue to work with the Village Manager’s office to coordinate FEMA reimbursement for Tropical Storm IDA related expenses. 7. Continue efforts with the Westchester County Planning Department to develop the Hazard Mitigation Plan and request funding that may become available. Cc: Village Engineer