Posts Tagged ‘workshop’

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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