Posts Tagged ‘flood’

HEC-RAS Workshop a Success!

Posted on: August 16th, 2019 by Tim Koch

The Ashokan Water­shed Stream Man­age­ment Pro­gram recently hosted a three-day work­shop on how to use HEC-RAS, a pow­er­ful com­puter pro­gram used to model flow in stream chan­nels. HEC-RAS is an acronym for the Hydro­logic Engi­neer­ing Center’s River Analy­sis Sys­tem. First released in 1995, its capa­bil­i­ties have grown sig­nif­i­cantly over time. HEC-RAS is now on its fifth ver­sion. It is often used to delin­eate the extent of the 1% annual chance flood­plain (aka, the 100-year flood­plain) among other reg­u­la­tory, tech­ni­cal, and envi­ron­men­tal uses.

Workshop participants use digital models of the terrain to help model how rivers behave during flood events.

Work­shop par­tic­i­pants use dig­i­tal mod­els of the ter­rain to help model how rivers behave dur­ing flood events.

This 3-day work­shop focused on using HEC-RAS to aid in the assess­ment and design of bridges and cul­verts. Milone and MacB­room, Inc. (MMI) were con­tracted to con­duct the hands-on work­shop to an audi­ence of twenty peo­ple. Par­tic­i­pants included staff and man­agers from County Depart­ments of Pub­lic Works and Town High­way Depart­ments within the West of Hud­son Water Sup­ply water­sheds. Oth­ers in atten­dance included flood haz­ard mit­i­ga­tion per­son­nel from NYC DEP, Stream Man­age­ment Pro­gram staff, DEC hydrol­o­gists, and folks from Riverkeeper.

HEC-RAS requires site-specific input data to accu­rately model flows and floods. Thus, the work­shop had a field com­po­nent where peo­ple were taught where to place stream cross sec­tions in rela­tion to the bridge, how to con­duct peb­ble counts to deter­mine size dis­tri­b­u­tion of sed­i­ment par­ti­cles on the stream bed, and how to mea­sure spe­cific com­po­nents of bridges and cul­verts required to build a HEC-RAS model. Only local data were used, and the work­shop cen­tered around mod­el­ing exist­ing con­di­tions and pro­posed alter­na­tives for an under-sized bridge in the Ashokan Reser­voir watershed.

Workshop participants investigate the Fox Hollow Road bridge over the Esopus Creek. Measurements taken on site were used to model different bridge replacement scenarios in order to increase community resilience during floods.

Work­shop par­tic­i­pants inves­ti­gate the Fox Hol­low Road bridge over the Eso­pus Creek. Mea­sure­ments taken on site were used to model dif­fer­ent bridge replace­ment sce­nar­ios in order to increase com­mu­nity resilience dur­ing floods.

It is impor­tant that bridges and cul­verts are sized prop­erly to pass flows that the struc­ture is likely to see over the course of its life. Under­sized bridges and cul­verts not only worsen flood­ing, but also frag­ment aquatic ecosys­tems and can cre­ate insta­bil­ity in the stream chan­nel that can prop­a­gate sig­nif­i­cant dis­tances upstream and down­stream from the struc­ture and lead to other damage.

This work­shop was aimed at empow­er­ing local engi­neers and high­way depart­ment staff to make informed deci­sions when man­ag­ing road-stream cross­ings (i.e., bridges and cul­verts.) Prop­erly sized cross­ings help to increase com­mu­nity resilience to cli­mate change, improve aquatic habi­tat, and help to main­tain water qual­ity in the Eso­pus Creek and its tributaries.

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Elevation and Floodproofing Workshop Advances Flood Mitigation

Posted on: April 12th, 2019 by Brent Gotsch
A workshop participant observes an engineered flood vent at the Elevation and Floodproofing Workshop held on March 26 and 27, 2019. Photo by Tim Koch.

A work­shop par­tic­i­pant observes an engi­neered flood vent at the Ele­va­tion and Flood­proof­ing Work­shop held on March 26 and 27, 2019. Photo by Tim Koch.

 

Poten­tially thou­sands of struc­tures across the NYC West of Hud­son Water­shed are located within mapped FEMA flood­plains. Many are located in down­town ham­let areas and are vital to the local econ­omy. More intense flood events and ris­ing flood insur­ance rates are threat­en­ing these struc­tures and the com­mu­ni­ties that rely on them for tax base, habi­ta­tion, eco­nomic activ­ity, and sense of place.

Prop­erty own­ers in flood zones are advised to reduce their flood risks and take action. A range of risk reduc­tion mea­sures are being tested and imple­mented across the coun­try. The Ashokan Water­shed Stream Man­age­ment Pro­gram brought speak­ers with national exper­tise to the region on March 26 and 27 to deliver a work­shop for local offi­cials to learn more about ele­va­tion and flood­proof­ing of struc­tures. The work­shop was held at the Emer­son Inn in Mount Trem­per and attended by nearly 50 build­ing depart­ment and other offi­cials from Ulster, Greene, Sul­li­van, and Delaware counties.

The work­shop fea­tured pre­sen­ters from Ducky John­son Home Ele­va­tions out of Hara­han, LA, and con­sul­tants recently retired from the NYS Dept. of Envi­ron­men­tal Con­ser­va­tion and the U.S. Army Corps of Engi­neers.

“Every dol­lar spent on mit­i­ga­tion saves six dol­lars in recov­ery costs,” said Rod Scott of Ducky John­son. “Ele­va­tion and dry flood proof­ing are proven flood haz­ard mit­i­ga­tion tech­niques used to reduce flood risk and flood insur­ance pre­mi­ums,” he said.

In the 2018 hur­ri­cane sea­son alone, U.S. ter­ri­to­ries expe­ri­enced 15 storms and 8 hur­ri­canes respon­si­ble for $50 bil­lion in dam­age. In response to this “new nor­mal” of bil­lions in annual losses due to prop­erty dam­age, Con­gress has man­dated flood insur­ance rate hikes for struc­tures with mort­gages in the FEMA floodplain.

“Ele­vat­ing or flood­proof­ing struc­tures pro­vides a way for com­mu­ni­ties to keep their build­ing stock, and their tax base sta­ble while also decreas­ing flood insur­ance pre­mi­ums for the own­ers and less­en­ing their risk of flood-related dam­age,” said Brent Gotsch, Resource Edu­ca­tor for Cor­nell Coop­er­a­tive Exten­sion of Ulster County and orga­nizer of the work­shop. “With increas­ing pre­cip­i­ta­tion pat­terns and more dam­ag­ing flood events, it’s vital that com­mu­ni­ties con­sider using these meth­ods to adapt and become more resilient,” he added.

Elevation and Floodprooging Workshop participants view an elevated home in Mount Tremper, NY. Photo by Brent Gotsch

Ele­va­tion and Flood­proof­ing Work­shop par­tic­i­pants view an ele­vated home in Mount Trem­per, NY. Photo by Brent Gotsch

 

Dur­ing the work­shop, local code offi­cials learned the dif­fer­ences between wet and dry flood­proof­ing and effec­tive ele­va­tion meth­ods for struc­tures. They learned how these prac­tices change flood insur­ance pre­mi­ums and how sim­ple mea­sures such as filling-in a base­ment can reduce pre­mi­ums by hun­dreds or even thou­sands of dollars.

A bus tour showed par­tic­i­pants local exam­ples of struc­tures retro­fit­ted with ele­va­tion and flood­proof­ing mea­sures. At one prop­erty, water­tight shields were installed to pre­vent water from flow­ing into the liv­ing area. Another stop fea­tured a res­i­dence with engi­neered “smart vents” that allow water to safely flow under­neath the structure’s first floor and equal­ize poten­tially dan­ger­ous pres­sures that could buckle the foundation.

At the end of the work­shop, local offi­cials left with increased knowl­edge about how to prop­erly retro­fit flood­prone struc­tures. Going for­ward, county part­ners plan to work with local munic­i­pal­i­ties to iden­tify and access fund­ing for ele­va­tion and flood­proof­ing projects and min­i­mize costs to prop­erty owners.

Addi­tional pre­sen­ta­tions by the Catskill Water­shed Cor­po­ra­tion, the NYS Divi­sion of Home­land Secu­rity and Emer­gency Ser­vices, and FEMA informed par­tic­i­pants about poten­tial fund­ing oppor­tu­ni­ties for ele­va­tion and flood­proof­ing projects. Pre­sen­ters walked through the appli­ca­tion process and gave advice on how to cre­ate a strong application.

Fund­ing for the work­shop was pro­vided by the New York City Depart­ment of Envi­ron­men­tal Pro­tec­tion.

A manager of a local bank branch shows Elevation and Floodproofing Workshop participants how they install the floodproofing barriers. Photo by Tim Koch.

The man­ager of a local bank branch shows Ele­va­tion and Flood­proof­ing Work­shop par­tic­i­pants how they install flood­proof­ing bar­ri­ers. Photo by Tim Koch.

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Olive Engineering Consultant Talks Flooding and Requests Resident Assistance

Posted on: July 15th, 2015 by Brent Gotsch

On July 14, the Town of Olive Flood Advi­sory Com­mit­tee (FAC) held a  meet­ing with town res­i­dents and Woidt Engi­neer­ing and Con­sult­ing to review ini­tial find­ings for the Local Flood Analy­sis (LFA)  in the ham­lets of Boiceville and West Shokan. George Fowler, an engi­neer with Woidt and the project lead for the LFAs, described what he and his team have dis­cov­ered. Woidt Engi­neer­ing and the Olive FAC will work together over the next few months to ana­lyze the pos­si­ble mit­i­ga­tion options for the ham­lets. Once these options are iden­ti­fied they will be run through the Benefit-Cost Analy­sis (BCA) process to deter­mine eli­gi­bil­ity for mul­ti­ple fund­ing sources. You can help with this process by fill­ing out a ques­tion­naire to report dam­ages to your home or busi­ness. This infor­ma­tion will used dur­ing the BCA process. The more infor­ma­tion we receive the bet­ter! It will be used to develop the most accu­rate results pos­si­ble. The form can be down­loaded here or picked up at the Olive Town Hall.

Not sur­pris­ingly, inun­da­tion of the busi­ness dis­trict in Boiceville is a major con­cern. George and his team showed how the high and tight val­ley wall forces the Eso­pus Creek to flood areas in that dis­trict dur­ing high flows. More analy­sis is needed but ini­tial find­ings show  there may be poten­tial to recon­nect the stream with its flood­plain just upstream of the Five Arch Bridge. Build­ing a flood­plain here may help keep water out of the busi­ness dis­trict or lessen the amount of water there. That project would likely require relo­cat­ing the fire depart­ment build­ing and other struc­tures in order to make room for water storage.

In West Shokan, the major prob­lems are asso­ci­ated with debris jams and sed­i­ment buildup. One of the major con­cerns for res­i­dents and Town offi­cials is the gravel bar just upstream of the Bushkill Bridge. The con­cern is that if the gravel bar grows it could cause an obstruc­tion that dam­ages or destroys the Bridge, cut­ting res­i­dents off from emer­gency ser­vices. George explained that we are liv­ing with the legacy of his­tor­i­cal human man­age­ment of the stream, namely the defor­esta­tion of the land­scape that occurred in the 19th Cen­tury that caused large pulses of sed­i­ment to enter the stream cor­ri­dors, and more recently dredg­ing and berming of mate­r­ial on stream banks that cre­ates unsta­ble stream cor­ri­dors. As with Boiceville, more analy­sis is needed, but one idea to explore is restor­ing appro­pri­ate stream chan­nel dimen­sions to help move sed­i­ment and debris through that area with­out undue buildup.

 

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Olive Residents: Flooding Problems?

Posted on: April 16th, 2015 by Brent Gotsch

If you are a res­i­dent of the Town of Olive and want to either view or add to flood maps you are wel­come to stop by the AWSMP office between 8:00 am and 4:30 pm, Mon­day through Fri­day.  Recently, the Town of Olive Town Board heard a pre­sen­ta­tion from Woidt Engi­neer­ing and Con­sult­ing on the Local Flood Analy­sis (LFA) process and how it will ben­e­fit the Town. Part of the pre­sen­ta­tion focused on Woidt’s desire to learn more from Olive res­i­dents about haz­ardous flood areas. Woidt cre­ated a set of maps where res­i­dents can mark  loca­tions of con­cern or known flood­ing and ero­sion haz­ards. Woidt will use the infor­ma­tion to exam­ine flood­ing solu­tions.  The maps are posted at the AWSMP office at 3130 State Route 28 in Shokan, NY (located between Ashokan Turf and Tim­ber and the Shokan Square plaza, across from the Citgo gas sta­tion). The maps will be avail­able for approx­i­mately three more weeks before they are returned to Woidt. For more infor­ma­tion on the LFA process in Olive please visit our office or view the Town of Olive web­site.

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Living by the Waterfront class offered March 21

Posted on: February 18th, 2015 by Brent Gotsch

Are you a prospec­tive home­owner think­ing of buy­ing water­front prop­erty? Do you already own water­front prop­erty but are con­fused about flood insur­ance or how to limit flood dam­ages? If so, you should attend the class “Liv­ing by the Waterfront—Keeping Dry When the Waters Rise”  at Cor­nell Coop­er­a­tive Exten­sion of Ulster County, 232 Plaza Road in Kingston, NY on March 21, 2015 from 9:00am to Noon. Cost to attend is $10 per per­son or $15 per cou­ple. Water­shed Edu­ca­tor Brent Gotsch will teach the class on what prospec­tive prop­erty own­ers should think about before pur­chas­ing water­front prop­erty. Reg­is­ter online by March 15. Con­tact Heather Eckardt at he54@cornell.edu or call 845–688-3047 for ques­tions about registration.

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