NJ's Somerset County Flood Information System and NWS' Middle Atlantic River Forecast Center: In Action to Notify and Project Local Flooding

I knew it had been raining since yesterday, but was the bridge (that I normally drove across to work) closed?

I opened my e-mail, and found a message, sent by Somerset County, New Jersey early this morning at 5:03 AM, notifying me that the bridge had been closed. Per suggestion of Mr. Carl Andreassen, the Principal Hydraulic Engineer for the County, I signed up for this
e-mail notification service about a month ago, and this is the first flood-related notification that I received.

Whenever the river level/stage rises up to seven (7) feet, the action stage, the police will be dispatched by the emergency services to close the bridge. The flood stage at this location is nine (9) ft. That is, the bridge will not actually be flooded until the water level reaches 9 ft. There is a stream gauge located close to the bridge; its measured water level is transmitted to the Somerset County Flood Information System via a satellite transmitter as well as a phone line, as a direct connection. The stream gauge is operated by the U.S. Geological Survey. See the picture for the actually measured water level, as indicated by the blue line.

The National Weather Service (NWS)'s Middle Atlantic River Forecast Center, via NWS' Advanced Hydrologic Prediction Service (AHPS), go further to project what the water level might actually approach. See the picture for the predicted water level, as indicate by the dotted green line.

According to the NWS' AHPS prediction, the bridge would remain closed through the evening during my commute home. Of course, I can check the actually measured water level right before I leave my office. I can also assume the bridge would remain closed until a further e-mail notice, a bridge re-opening notice, from Somerset County.

It is nice to live in the information age!

Credit: The image above was made from the NWS's MARFC website.

My presentation contains additional info on flood forecast and warning as well as other aspects of urban flood management.

Water Main Bursts in Franklin Township, New Jersey

In the late morning of November 18, 2008, a 60-inch water main broke in Franklin Township, Somerset County, New Jersey. The burst had a ripple effect on 100,000 customers in Somerset, Middlesex and Union counties, prompting officials to close schools and residents to boil water. (Both my home and office were affected.)

Complaints ranged from low water pressure to no water at all in 18 towns, said Richard Barnes, a spokesman for New Jersey American Water. As a precaution, the utility issued a boil water advisory.

The rushing water eroded the earth underneath the road, washing away part of Weston canal Road. Water gushed into the Delaware and Raritan Canal. (See the picture.)

The main is a major pipeline for transmission of water, and was first installed in 1958.

Although the cause of the break is still under investigation, this incident again highlights the urgent need for condition monitoring and rehabilitation of the nation's water infrastructure.

(Info Source: The Star-Ledger. Photo Credit: Ed Pagliarini, MyCentralJersey.Com)

Hurricane Gustav on News Orleans: A Narrow Miss

Gustav has made the landfall near Cocodrie, Louisiana, 72 miles southwest of New Orleans, as a category 2 hurricane. New Orleans has avoided a direct hit, what a relief!

Map to the left shows the levee system to protect New Orleans. The levee system was breached at numerous locations during Hurricane Katrina (category 3) three years ago. The levee system has since been repaired to or beyond the pre-Katrina protection level. However, the levee system planned by the US Army Corps of Engineers to protect the city from a "100-year storm" is still being re-built or newly constructed and will not be completed by 2011.

It should be pointed out that the strength (height and speed) of a surge at a specific location depends on the approaching angle of the hurricane as well as the type and length of the channel that the initial surge would have to travel through, not just the category number. Highly sophisticated computer models are available and can be used to forecast the flood level more accurately.

I applaud the coordinated efforts by Federal, State, and local authorities to successfully inform and evacuate residents in advance. Forecasting the flood level is not yet an exact science, but it is better to be safe than sorry.

For Gustav, the surge water has now entered the city canals, and some water is splashing over the top of the Industrial Canal (the Inner Harbor Navigation Canal on the map). May the levee system in New Orleans continue to hold and the water drainage/pumping system continue to function to minimize the property damages!

(Source of Map: 2006 Report by the US Army Corps of Engineers)

The Stellwagen Bank National Marine Sanctuary

My family and I visited Cape Cod and Boston last weekend. Photo to the left shows a family of four whales (two parents above water and two babies under water) hanging around our tour boat. Awesome!!!

My album contains additonal photos of the whale watching.

Fish Ladder at Lake Lenape Dam, Mays Landing, New Jersey

I visited Lake Lenape Dam yesterday. It is about 20 miles west of Atlantic City.

The photo to the left shows a fish ladder that was constructed at the dam in 2006. The fish ladder provides passage for migratory fish with access to 15 miles of upstream spawning and foraging habitat. The dam is co-owned by Atlantic County and Hamilton Township.

Entrance is adjacent to the spillway discharge (on right side of the photo) at invert elevation of 1 foot below the mean sea level. The ladder exits into the lake (on left side of the photo next to the non-operating powerhouse) at invert elevation of 8.3 feet above the mean sea level. The fish ladder is 200 feet long.

A beautiful lake, a beautiful water fall (spillway discharge), a renewable source of energy, plus happy fish! What more we could ask for from a good old dam?

My album contains additional photos of the dam.

Iowa City Flood 2008

Photo to the left shows the flooded Iowa River at the renowned University of Iowa hydraulics lab on June 14.

I visited the lab twice in the past. Folks there actually used a real fish to test how it would move up the fish ladder. The fish ladder is installed at many dams, and is a life passage for migratory fish such as salmon.

(Photo Credit: James Hemsley)

Update 6 (Final Update): A Great Success in "Quake Lake" Draining! Congratulations to Chinese Engineers! (唐家山堰塞湖排水获巨大成功! 热烈祝贺中国工程师们!)

A deep channel has cut through the landslide dam by the "natural" current. See photo to the left for the initially cut through channel around 9:00 a.m., June 10, Beijing time, with lake water surface elevation of about 742 m and discharge rate of about 1,200 cubic meters per second. Channel inlet bottom elevation was cut down from 740 m to about 720 m (about 20 meters lower) and channel was cut wider from about 10 m to about 150 m. The lake water level was brought down from its highest at 742.96 m (8:00 p.m., June 9, Beijing time) to the present reading of 719.48 m (8:00 p.m., June 10, Beijing time). As a result, over 100 million cubic meters of the lake water was drained out of the lake. The population at risk of future downstream flooding has been reduced from 1.3 million (upon catastrophic collapse of the landslide dam) to 50,000.

Although the peak discharge rate was very high at 6,420 cubic meters per second during the course of channel cutting and lake water draining (and was rapidly increased to this peak value from 500 cub. m/s within three and half hours, from 7.56 a.m. to 11:30 a.m. on June 10), the downstream area flooded by this release of water was far less than the planned 1/3 dam collapse inundation zone. Note over 200,000 people were already evacuated about 10 days ago, in preparation for the possible 1/3 dam collapse scenario. Therefore, I would define this initial draining of the "quake lake" water as a great success! The engineers' original drainage scheme including the sluice channel design worked.

Congratulations to the Chinese engineers for their great success!

P.S.: I am also glad that my projection of the unnecessary second, deeper drainage channel to "force" an additional outflow was correct (see my Update 5 posted on June 8). Construction of the second channel was stopped at 6:00 p.m., June 9 as the lake outflow through the first already-constructed channel increased to 81 cubic meters per second (cms) and was approaching the lake inflow rate of 115 cms.

Photo credit and info source: Xinhuanet