It’s a change that likely won’t go noticed by many Alexandrians, but the city is making an adjustment to its manholes that could have an impact on flooding during storms.
According to Flood Action Alexandria — an ongoing newsletter highlighting flooding issues and mitigation measures in Alexandria — the City of Alexandria is working on finding a contractor to install 870 stainless steel manhole inserts around the city.
“Manhole inserts are pan-shaped devices that sit at the top of the manhole, directly underneath the manhole cover,” the newsletter said. “They prevent stormwater inflow from gushing to the sanitary sewer after it enters the hole in the manhole cover.”
The inserts have a hole that slowly trains accumulated stormwater after the storm ends. The idea is to reduce inflow into the sanitary sewer system, which often becomes backed up during storms and contributes to flooding.
A map of where the manhole inserts will be located is shared online.
The newsletter also shared some updates on other flooding projects. The combined Commonwealth and East Glebe Road and Ashby and East Glebe Road project — which will increase the capacity of the storm sewer system — is in contract negotiations with an engineering firm ahead of moving into the design phase.
Two spot improvements, one at Oakland Terrace Timber Branch and another on Mount Vernon Avenue, are entering the construction phase.
The National Weather Service has issued an areal flood warning for Alexandria.
“Avoid small streams and do not drive through water on roadways,” a release from the city said.
The warning is in effect until midnight tonight.
According to the National Weather Service:
…FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT TONIGHT…
* WHAT…Flash flooding caused by excessive rainfall continues to be
possible.* WHERE…Portions of DC, Maryland and northern Virginia, including
the following areas: in DC, District of Columbia. In Maryland,
Anne Arundel, Carroll, Central and Southeast Howard, Central and
Southeast Montgomery, Northern Baltimore, Northwest Harford,
Northwest Howard, Northwest Montgomery, Prince Georges, Southeast
Harford and Southern Baltimore. In northern Virginia,
Arlington/Falls Church/Alexandria, Eastern Loudoun and Fairfax.* WHEN…Until Midnight EDT tonight.
* IMPACTS…Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.* ADDITIONAL DETAILS…
– Showers and thunderstorms are expected this afternoon into
the evening as a cold front pushes through the area. Heavy
rainfall rates could produce localized rainfall amounts of 2
to 3 inches in a short period of time.
The City of Alexandria has launched a new interactive map that lets locals keep track of flood mitigation projects around town.
The interactive map shows all 35 ongoing projects around town, as well as two recently completed ones and seven future projects.
Intense flooding in recent years pushed the issue of flood mitigation into the limelight, pushing some local citizens to flood mitigation activism. While the city has moved forward on several flood mitigation projects, the new map is helpful for keeping track of those.
Clicking on each dot pulls up a snapshot of the project with information like cost, funding source, and a project timeline.
“This ‘project dashboard’ is a digital Geographical Information System (GIS)-based tool that allows users to view more than 40 currently-identified flood mitigation projects from a list or on a map to view the proposed solution, cost and estimated implementation schedules, among other information,” the city said in a release. “To explore information about the projects, click on the dots on the map. A window will pop up with information, including the type of project, status, cost, funding source and estimated construction start date.”
The National Weather Service has issued an Areal Flood Watch for Alexandria with rain expected this afternoon and most of this weekend.
While it’s clear skies this morning, the forecast for rain comes after heavy rainfall last night.
“Avoid small streams and do not drive through water on roadways,” the City of Alexandria said in a release.
From NWS:
1020 AM EDT Fri Aug 5 2022
…FLOOD WATCH IN EFFECT FROM 3 PM EDT THIS AFTERNOON THROUGH THIS EVENING…
* WHAT…Flash flooding caused by excessive rainfall is possible. […]
* WHEN…From 3 PM EDT this afternoon through this evening.
* IMPACTS…Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations.
* ADDITIONAL DETAILS…
– Showers and thunderstorms will develop this afternoon and may last into the evening. Any thunderstorms will be capable of producing very heavy rainfall, with localized totals of two to four inches possible. Much of the rain may fall within a one to three hour period, making rapid rises in creeks and streams possible, as well as flash flooding in urban areas.
– http://www.weather.gov/safety/floodPRECAUTIONARY/PREPAREDNESS ACTIONS…
You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.
Some of the city’s biggest flood mitigation projects have been making progress in recent months.
In the same Flood Action Alexandria newsletter that highlighted some record-breaking rainfall in July, the city said two of the top-ranking, large capacity flood mitigation projects have “reached notable milestones.”
The first is that a firm has been selected to handle the project at Commonwealth Avenue and East Glebe Road/Ashby Street and East Glebe Road, two separate plans mergedearlier this year into one $50 million project. The city is currently in negotiations with the selected firm.
According to the newsletter:
The project, which combined two projects in adjacent neighborhoods, will increase the capacity of the storm sewer system to allow stormwater conveyance. The project will also incorporate low impact development elements — commonly referred to as “green infrastructure” — to allow stormwater to soak into the ground to reduce runoff. A grant from the Virginia Community Flood Preparedness Fund awarded to the City in October will support portions of these projects. The estimated cost for design and construction is $50 million.
The second project is the Hoofs Run culvert bypass, and the newsletter says the city hasn’t selected a firm yet but has narrowed its list of qualified contractors.
“The project will carry water from Timber Branch in a new stormwater management system that involves conveyance to improve the system’s performance and reduce flooding,” the newsletter said. “The estimated cost for design and construction is $60 million.”
More information on both projects is available on the city website.
A storm that postponed the city’s birthday celebrations last month set a rainfall record in Alexandria according to a floodwater mitigation newsletter prepared by the city.
The Flood Action Alexandria newsletter, prepared by Flood Action Alexandria communications specialist Amanda Dolasinski, noted that a storm on July 9 set the record for rainfall recorded before 7 a.m. The newsletter said the city saw nearly 4 inches of rainfall in the northeast section of Alexandria and pushed Four Mile Run to to the 10-foot stage at Shirlington Road Bridge.
“The Four Mile Run rain gauge in the northeast part of the City recorded 3.92 inches of rain at the 24-hour mark of the July 9 storm, with most rainfall recorded before 7 a.m.” the newsletter said. “The storm was classified as a 10%- to 12%-chance-per-year storm, meaning the rainfall produced exceeded the probability with a 10% chance of being equal in any given year.”
Despite the quantity of rainfall, the newsletter said the intensity was less dramatic and the city didn’t see the same levels of severe flooding as it has in the past.
“Fortunately, the intensities were less dramatic than in past large storm events,” Brian Rahal, a civil engineer for the Stormwater Management Division, said in the newsletter. “It appears the urban flash flooding was at a minimum.”
Alexandria and areas nearby are under a Severe Thunderstorm Watch this evening and a Flood Watch.
The National Weather Service issued a Flood Watch earlier today (Monday), cautioning flooding may occur this evening and a Severe Thunderstorm Watch is in effect until 10 p.m.
“Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations,” the Flood Watch reads. “Afternoon to evening showers and thunderstorms may produce very heavy rainfall capable of flash flooding. This could include multiple rounds of storms which would enhance the flood risk. Rainfall rates may reach 1 to 2 inches per hour, locally higher in spots. The D.C. and Baltimore metros will be the most susceptible given recent heavy rainfall the past couple of weeks.”
The National Weather Service advises residents to monitor forecasts and be prepared in case of flash floods.
A Severe Thunderstorm Watch is in effect through 10PM tonight. The primary threats for storms today are damaging winds and isolated tornadoes. #DCwx #MDwx #VAwx #WVwx pic.twitter.com/BeKEyqBjAV
— NWS Baltimore-Washington (@NWS_BaltWash) July 18, 2022
Alexandria leaders will be on-hand on Thursday, July 14, for the unveiling and dedication of AlexRenew’s RiverRenew Tunnel Project.
The $454.4 million project will replace Old Town’s 19th century combined sewer system with a tunnel system, sewer infrastructure and improvements to AlexRenew’s wastewater treatment plant — all to prevent 130 million gallons of combined sewage from flowing from four outfalls into the Potomac River every year.
The dedication will be held on July 14 from 9 to 11:00 a.m. at the Alexandria Renew Education Center and Meeting Space (1800 Limerick Street).
The Virginia General Assembly mandated in 2017 that the project be completed by July 1, 2025. The groundbreaking for the project was held last fall.
The tunnel project is partially funded through a $321 million loan from the Environmental Protection Agency’s Water Infrastructure Finance and Innovation Act and $50 million from the American Rescue Plan Act.
Late last month, a RiverRenew tunnel boring machine was delivered to the project site.
Bon voyage! It's full-steam ahead for the #ALXTBM!
Our paparazzo captured this shot of her loading onto the barge that'll take her up the Chesapeake Bay.
Stay tuned to learn how to catch a glimpse of her arrival in Alexandria the week of July 4! pic.twitter.com/4in4Oq3Kyy
— Alexandria Renew Enterprises (AlexRenew) (@AlexandriaRenew) June 27, 2022
The City of Alexandria has a handful of irons in the fire when it comes to stormwater management, but one new approach is one of the oldest tactics: storing runoff in rain barrels.
The city announced yesterday that it’s planning to offer a limited supply of free rain barrels, with more available via raffle at the city libraries.
“The City of Alexandria Transportation and Environmental Services (T&ES) Stormwater Management Division will be offering a limited supply of free rain barrels to residents living in the City,” the city said in a release. “Complete the application form by July 31 to register for a free rain barrel. Additionally, a limited number of rain barrels will be reserved for raffles at each of the four library branch locations in the City.”
Those hoping to get a rain barrel must be city residents and have to demonstrate how and where the barrel will be used — presumably to collect rainwater.
“The City encourages the use of rain barrels which capture and store runoff from roofs that would otherwise be directed into the storm sewer network,” the release said.
The city said additional benefits include collecting water to use in gardening and the user is eligible for a credit towards the stormwater utility fee for installation and proper use of a rain barrel — the latter incentive is particularly relevant with stormwater utility fees going up this year.
“This program is in partnership with the Northern Virginia Rain Barrel Partnership Program, sponsored through the Northern Virginia Soil and Water Conservation District,” the release said. “The Partnership hosts build-your-own rain barrel workshops throughout the Northern Virginia area.”
https://twitter.com/AlexandriaVATES/status/1542221401582698501
Photo via Waldemar Brandt/Unsplash
A severe thunderstorm warning has been issued for Alexandria and the city is starting to see heavy rainfall.
The city is also under an areal flood watch.
“The National Weather Service has issued an Areal Flood Watch for Alexandria,” the city said in a release. “Avoid small streams and do not drive through water on roadways.”
The thunderstorm warning comes almost a week after a severe thunderstorm knocked out power to portions of the city until Monday afternoon.
From the National Weather Service:
BULLETIN – IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Baltimore MD/Washington DC
1147 AM EDT Fri May 27 2022The National Weather Service in Sterling Virginia has issued a
* Severe Thunderstorm Warning …
* Until 1230 PM EDT.
* At 1146 AM EDT, severe thunderstorms were located along a line extending from Lansdowne to near Chantilly to near Lake Ridge, moving northeast at 40 mph.
HAZARD…60 mph wind gusts.
SOURCE…Radar indicated.
IMPACT…Damaging winds will cause some trees and large branches to fall. This could injure those outdoors, as well as damage homes and vehicles. Roadways may become blocked by downed trees. Localized power outages are possible. Unsecured light objects may become projectiles.
* Locations impacted include… Arlington, Alexandria, Germantown, Centreville, Rockville, Bethesda, Gaithersburg, Reston, Annandale, Clinton, Olney, Springfield, College Park, South Riding, Fort Washington, Herndon, Greenbelt, Fairfax, Langley Park and Beltsville.
PRECAUTIONARY/PREPAREDNESS ACTIONS…
A Tornado Watch remains in effect until 200 PM EDT for District of Columbia…central Maryland…and northern Virginia.
For your protection move to an interior room on the lowest floor of a building.
A Tornado Watch remains in effect until 200 PM EDT for District of Columbia…central Maryland…and northern Virginia.
