Weather or not: predicting floods

DAVID HULSE
Posted 10/10/18

NARROWSBURG, NY — “This is a really pertinent topic for us,” Chairman Aaron Robinson said in introducing the Upper Delaware Council’s (UDC) October 4 guest speaker. Jim …

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Weather or not: predicting floods

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NARROWSBURG, NY — “This is a really pertinent topic for us,” Chairman Aaron Robinson said in introducing the Upper Delaware Council’s (UDC) October 4 guest speaker.

Jim Brewster, of the National Weather Service’s (NWS) Advanced Hydrologic Prediction Stream (AHPS) Service in Binghamton, decides when to post flood warnings on the Delaware and its tributaries online at forecast.weather.gov.

Brewster provided five pages of technical background to preface his presentation, which was largely a primer on finding and using the incredible amount of data available on the NWS site. The basic explanation appears in the first lines of that data.

“The NWS uses river forecast models to estimate the amount/levels of water flowing through the U.S. rivers. These models estimate the amount of runoff a precipitation event generates, computes how the water will move downstream, and then predicts the flow of water at a given location (AHPS forecast point) throughout the forecast period (every six hours, out three to five days in many locations).”

Beyond the models, forecasters get observed information from rain gages, river water level or flood stage, gages and radar estimates. That data gets fed into the model. Other variants in the model may include snow melt, groundwater levels, reservoir operations and routed water from upstream. Forecasters project three days ahead of observed levels, but Brewster emphasized that those are only educated-guesses.

Once it’s on the ground, water can be quantified, but rainfall is the wildcard, Brewster said. “We try to predict rainfall. In the 25 to 30 years I’ve been doing it, I’ve found that is almost impossible to do. We do our best,” he said.

Brewster is in the process of a five-year review of NWS mapped, flood-susceptible areas in the valley, which involves talking to residents and emergency services and checking for any areas left uninhabited after flooding.

Several federal departments have a finger in flooding questions: NWS (Commerce Department) computations are used by the Delaware River Master (Department of the Interior) in calling for reservoir releases to augment river flows, but they are not used by the Federal Emergency Management Administration (FEMA—Department of Homeland Security), which administers flood insurance.

The issue of the wide separation between Upper Delaware River gages has been argued by residents cyclically for decades. There are only two between those at Lordville and Port Jervis, a distance of some 50 miles. Unsure which agencies may control them, Brewster said NWS has no role in their installation. “You’d have to get in touch with your vendors,” he said when asked about them. 

On the agenda

UDC voted to award $11,387 through its fiscal year 2019 Technical Assistance Grants (TAG) program. Grants go to: Shohola Township ($5,000 for zoning ordinance amendments), the Town of Tusten ($5,000 to acquire and install an electronic system for document management, planning and training), the Town of Lumberland ($787 to create and print 2,000 copies of a “Guide to Permits” for new and prospective property owners) and Berlin Township ($600 for the creation and printing of 1,000 copies of a guide to township municipal services). UDC TAG grants totaling $868,575 have funded 253 member-town projects since 1988.

The council named a sub-committee consisting of delegates David Dean of Deerpark, Jim Greier of Fremont, Larry Richardson of Cochecton and Peter Golod, UDC Resource Specialist, designated to meet with Town of Highland officials to resolve a zoning-review issue caused by the town’s failure to provide documentation needed for UDC’s compatibility review of a building project in Barryville. The issue has gone unresolved since May of this year. No date for the meeting had been agreed as of October 4.

The council reported receipt of four additional responses to its recent River-Related Law-Enforcement Survey, from the townships of Westfall and Damascus and the towns of Delaware and Tusten. Five towns—Lumberland, Shohola, Deerpark, Hancock and Highland—had replied by September 6. Among other things, the survey asked if they would be interested in receiving NPS funding to “help subsidize river-related recreational law enforcement…,” and if they would be able to pay a federally established wage rate of $36.38 per hour plus benefits.

Most said “yes” to federal funding, but all but two rejected providing the proposed wages and benefits. NPS Superintendent Kris Heister said she felt the officials filling out the forms had not realized that NPS would be providing wage and benefit funding, so she said, “Those who said ‘yes’ to the funding would likely be positive about the program.”

UDC also received letters from the New York State Department of Transportation rejecting a request to retain the New York-shore bridge construction access in Pond Eddy for emergency access, but leaving the door open to considering aiding in development of an emergency access at a nearby existing downstream access.

They also received a copy of Rep. John Faso’s September 12 letter to New York State Department of Environmental Conservation (DEC) Commissioner Basil Seggos querying Seggos about DEC plans for “additional testing it will take to ensure that we can find resolution to these issues with the Barnes Landfill,” and offering to meet with DEC staff about it.

Narrowsburg, udc, delaware river

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