Mean High Water

Mean High Water: A tidal datum.  The arithmetic mean of the high water heights observed over a specific 19-year Metonic cycle (the National Tidal Datum Epoch).

A very precise definition of MHW can be found in the "Tide Tables" or the AUXNAV text or any of a dozen or more references.  Members of the Auxiliary that have dealt with them can give a much briefer and less academic definition of Mean High Water.

FLOODS

Division VI members had an opportunity to renew their MHW acquaintance last October when, once again, much-heavier-than-usual rains sent rivers and bayous in the Houston area out of their banks and into surrounding neighborhoods.

Although not an uncommon occurrence, the floods of late 1994 set a number of not-to-be-envied records: rainfall totals 15-18 Oct. measured 22-to-30 inches, depending on specific locations; totals were 25-to-87 percent above anticipated 100-year rainfall levels; hundreds of homes outside the 100-year flood plains were destroyed; and washed-out hydrocarbon pipelines burst and ignited and the waters literally burned for several days. Media reports indicated more than 11,500 people were forced from their homes and, most tragically, 19 people died.

What can an Auxiliary crew expect when faced with challenges of that magnitude? We hope the experiences of "Sea Search" and her operator, Darrell Middleton of FL 68, and crewmen Mack Price, FL 68, and Evan Davies, FL 65, can aid in preparing you for your next flood callout.

The Coast Guard requested Auxiliary assistance to evacuate residents from the San Jacinto River area east of Houston and north of I-10 on Oct. 18. At that location, according to USGS statistics, the "San Jac" was flowing at a rate of 360,000 cubic feet per second, 359,000 cubic feet above normal! The river was 26 feet above its median level and the current was16 feet per second, almost 10 knots (some media reports said 45-to-60 knots!). By comparison, Galveston Bay tidal currents through the jetties are slightly more than two knots and the awe-inspiring 40-foot tidal ranges in the Bay of Fundy have maximum velocities of only four knots.

While 10-knot-currents may not sound dangerous, they can vary significantly around structures and in constricted areas creating dangerous eddies and swirls. One such current caught Sea Search as it was being held against a house to evacuate a resident, swung it around and partially under a second-floor porch making a temporary fender of Price against the bridge enclosure and resulting in minor scrapes and bruises which were the only injuries during the mission.

Expect the unexpected. Be prepared to deal with it. Be flexible. Be careful.

Sea Search is ideally suited for this type mission. A 22-foot PennYan with a 225 horsepower inboard and tunnel drive, SS has the 18-inch draft necessary to navigate flooded streets and the power to get in and back out with a load of evacuees. And Middleton is the ideal operator: experienced with his boat, calm and steady at the helm for hour after long hour and virtually unflappable.

Don't volunteer your boat if it is lightly powered or deep draft, you'll probably end up part of the problem. And don't volunteer if you can't tolerate the thought of gouges in your gelcoat--you're going to have them. Or if chaos bothers you, because that will be your world for awhile.

Forget formal navigational procedures, you're in uncharted waters because water isn't supposed to be where you are--that's why you're there. Middleton and Price were half way through an AUXNAV class at the time but plotting fixes and calculating set and drift simply aren't practical when the river is more in control than you are. Your three best navigational tools are street maps, USGS 1:24,000 topographic maps and, best of all, a crew member with detailed local knowledge. A civilian who had lived and worked in the area came aboard Sea Search and was absolutely invaluable. Your Navaids will be street signs, half submerged buildings and local landmarks. The river itself will lose its definition and its 100-yard width will be lost in a swift-moving blanket of water that may be a mile wide. Stop signs, mailboxes and other neighborhood niceties such as yard fences will become world-class gelcoat eaters.

Sea Search was vectored to some rescues by house number. But remember, electric power will be one of the first victims of flood waters so carry as many high-powered flashlights and search lights as you can get. Human victims may be trapped well out of ready visibility--that's why it's called Search and Rescue. Sea Search was on the water from about 1730 Oct. 18 until 1030 Oct. 19 and for several hours before dawn had to battle fog as well as the flood.

Mentally review all aspects of your first aid training and as much psychology as you can muster. You may be called on to use any or all in the course of your mission. The Sea Search crew had to deal with minor hypothermia, fear, resignation, reluctance (some people don't want to abandon even a flooding home), minor scrapes and bruises and even incomprehension.

Some veterinary training would also be handy. People don't want to abandon pets and you can't very well tell them to pitch Fido back into the torrents. But be aware that little Fifi can become Fang when faced with a bunch of strangers in a stressful situation. And it can be almost impossible to convince a 100-pound Laborador that loading him into a strange boat is in his best interest. Calm and patience can be your best friends in those circumstances.

Fortunately Sea Search didn't encounter any snakes but they, too, are seeking safety and most of them are going to be deadly. Be especially careful around any apparently safe high ground, building overhangs, and trees. You do have to draw the line somewhere. A dappled grey horse that had found a small patch of high ground was bypassed several times as other evacuees were ferried to safety--Sea Search is not equipped with stock racks!

Trees. A particularly loathsome hazard to navigation. Their lovely, leafy branches hide just beneath the surface, sometimes at amazing distance from any visible tops, and reach out to grab you at every opportunity. While trying to find a path under an electric power line lower than its 6' hard top, Sea Search was swept into a tree's upper limbs which gouged an 18-inch cut completely through the hull at the starboard quarter gunwhale. The current then slammed the boat onto the roof of a house as it manuevered free of the tree--a fact reported on national television as "one rescue boat ran aground on the roof of a house."

Trees are also an especially dangerous form of flotsam--they tend to grab a boat, hang on and take it with them. Debris in the water will be everywhere and everything: from trees, to barrels, to boards, to parts of houses, to small buildings, to, well, you name it. Operators and lookouts must be constantly alert, particularly in low visibility. And resign yourself. Pick the smallest, softest-looking pieces and take them with your bow. You'll never miss them all.

Communications--another not-by-the-book operation. Your on-scene authorities will be local volunteers who haven't taken an AUXCOM course. Do it their way. Sea Search made status reports to USCG MSO Houston and was in constant communication with several CG boats in the area while the command post was operated by a volunteer fire department. They did an outstanding job--even furnished coffee and doughnuts--and arranged for a local company to provide a gasoline truck. Their people in charge knew the area where help was most critically needed and they stayed in touch with a "handheld" but comm procedures definitely weren't "by-the-book." Staying in touch with all boats operating in your area can be complicated by the fact that many public safety vessels don't carry VHF radios. Be natural and be clear. Don't try to impress with your prowords and CGAUX abbreviations but don't go "10-4 Good Buddy" either.

A cellular phone can be a big help. It could prevent you becoming a flood victim. One CG boat had radio trouble and with no "local" aboard when the fog settled in, was in serious navigational difficulty. Hailing Sea Search when they saw its emergency light, the crew found themselves a guide through some pretty tricky back waters to the command post. (After Sea Search couldn't find a way under the power line a CG "jon" boat did and brought a possible heart attack victim back to the Command Post for medical attention--favors even out.) Using flooded roads as boat ramps leaves a lot to be desired and won't do a lot for your keel but area marinas and ramps will probably be useful only to submarines.

Sea Search was launched by sling at MSO Houston on Oct. 18 and was hauled out onto its trailer on Wallisville Road Oct. 19 because its cabin height wouldn't permit it to cross under I-10 as it had been able to do the previous evening. That's a long time on the water but time clocks lose their significance when people are in rising water and asking for help.

The crew of Sea Search, however, had no strangers to overtime: Operator Middleton, a Building Technician with AT&T Houston, is a Navy veteran and qualified submariner. He received USCG commendation for SAR missions following flooding on the Brazos River southwest of Houston in 1992. Price is a retired public affairs official from Panhandle Eastern Corporation in Houston Also a Navy veteran, and qualified Surface Warfare Officer in destroyers, he participated in SAR missions in the Atlantic, Pacific and Arctic while on active duty. Davies is a PhD candidate at Rice University and was making his first large-scale SAR mission. Middleton and Price, respectively, became VFC and FC of FL 68 Jan. 1, 1995.

Is it worth the effort, damage to equipment and risk of injury, or worse? Sea Search brought 19 people and eight dogs to "high ground" and turned them over to the care of emergency units at an I-10 exit ramp. More were brought out by other boats. Local and national televison audiences were stunned the next morning by "live" coverage of a roaring inferno resulting from a ruptured gasoline pipeline.The flames were shooting straight up the evacuation routes Sea Search had used to ferry some of those flood victims to safety!

I sometimes wonder about the grey horse.

Addendum 1:

Feb. 16, 1995 Middleton and Price were presented the USCG Auxiliary Plaque of Merit by ADM Robert E. Kramek, Commandant, United States Coast Guard during award ceremonies in Pasadena, Texas. Davies received the award from MSO Houston prior to leaving the country for an extended period to pursue field work for his doctorate.

Addendum 2:

June 15, 2006…Middleton and Price both served as FC of Flotilla 68 Clear Lake and Price served as Captain of Div. 6, D8CR.

Note: the following is quoted from the USCG AUXILIARY MANUAL "Plaque of Merit, given in recognition of extreme skill in performing an assist or rescue that involves risk to the Auxiliarist's life."

Feb. 18, 1995 The crew of Sea Search and a number of other area Auxiliarists received the Coast Guard Unit Commendation with Operational Distinguishing Device during Div VI awards ceremonies in Houston, Texas "for exceptionally meritorious service" during the San Jacinto River floods and subsequent cleanup actions. Regular and Reserve units had received the commendation during the 02/16/95 ceremonies.