Uh oh…

I was just thinking how fortunate it was that relatively little snow fell on the upland portions of the Delaware River watershed last weekend, until the most recent storm watch came through this morning.

If it comes to pass as predicted and eastern Pennsylvania is where the next storm converges and “explodes” then Philly will end up with three to four feet of snow on the ground and the rest of the watershed going north could have two to three feet.

Creeks and rivers in the lower watershed (Brandywine, Perkiomen, Rancocas, Assunpink, etc.) will face an extreme risk for flooding. The big rivers (Delaware, Lehigh, Schuylkill) will also be looking at a really dangerous situation if there is a rainstorm and rapid snow melt, coupled with the potential for ice jams.

Maybe this storm will miss us. And if it does hit perhaps we will enter a long dry warm-up that takes us safely into spring.

Stay tuned.

Compelling read…

Finally, I am reading the second edition of “DAMMING THE DELAWARE: The Rise and Fall of Tocks Island Dam.”

I have a signed copy from the author, Richard C. Albert, who wrote: “Best wishes to a fellow River Rat.” Dick passed away unexpectedly a few months ago.

I read the first edition about seventeen years ago when I just beginning to lay the foundation for my own knowledge base about the river.

This reading is being undertaken with a very different perspective. I’ve left off with the Sunfish Pond chapter, which tells the story of how close this jewel along the Appalachian Trail came to being bulldozed, expanded and pumped.

Damming the Delaware starts out with the earliest controversies (eighteenth century) right to the Tocks Island battle. If you’re interested in the river read it as soon as possible.

Six weeks until Spring…

February can bring brutal winter weather at a time when most of us are tiring of the cold. There is solace in the fact that whatever comes won’t stick around for long and the days are getting longer.

In a few weeks the migrating ducks will be hanging out in the Lower Delaware River, patiently waiting for the ice to melt up north.

One of the smallest of these migrants is the Bufflehead. Strange looking birds they are because their ‘buffalo heads’ seem somewhat oversized for their small bodies.

Take a trip up River Road in a few weeks and you’ll probably see buffleheads, hooded merganser and other early migrants. The stretch between Morrisville and New Hope is a prime area to look for the early harbingers of spring.

Frigid Waters…

It’s frigid but not entirely frozen down at the extreme lower end of the non-tidal Delaware River. Chunks of ice were floating by the Calhoun Street Bridge in Morrisville this morning.

An essential tool for those interested in rivers and creeks is the NWS Hydrology page (this links you the Mt. Holly station). There you find the ANNUAL WINTER/SPRING FLOOD POTENTIAL STATEMENTS and much more (ice buildup, snow cover etc.).

 

Right now the flood potential is deemed to be “above normal.” Just a few days ago the Delaware River at Riegelsville gage surged to almost 16 ft. (six feet below flood stage). The river continues to run well above the median flow for January 30 at the Belvidere gage (15,000 cfs compared to 5,000 cfs).

The tributaries are running a bit above normal but that should change over the next string of dry days.

While we typically have little to no ice buildup on the lower Delaware River (with huge exceptions like the Winter of 1996 Ice Flood) the more telling ice and snow statements come from NWS’s Binghampton, NY station, which covers all of the Upper Delaware River.

As of this weekend there is little snow pack in the upper watershed, although thick ice covers the large eddies in the Pocono/Catskill reach of the river. Ice buildup sets up one of the conditions needed to cause a specific type of flood along the Delaware. A quick thaw and heavy rain on top of snow pack and ice jams can create a serious threat to communities along the river. The NYC reservoirs have no impact on this particular flood scenario.

With luck the coming spring thaw will happen gradually without any big storms so we don’t have a repeat of the April 2005 flood.

Storm heading our way...

A Flood Watch has been posted for small streams and rivers in our region. There isn't much snow around on the ground anywhere in the watershed except the mountains, where the deepwater is also still iced over.

The Delaware River, Lehigh River and most smaller creeks and rivers are running at or slightly below normal so even 2 inches of rain should not pose much of a threat for those living along a flood prone stream.

The good news is that most of the rain will be come down overnight tonight and we'll have great conditions for paddling.

Bad news is there will be a return to frigid weather by the end of the week and I am in not fit to paddle the canoe for at least 2 or maybe 3 weeks.

Winter Rivers...

Wading River - January 13, 2010 (photo by Chris Meyers)

I'm averaging less than one canoe trip per week and that won't change until March. The most recent was a wonderful winter trip on the Wading River, a pretty little stream in the New Jersey Pine Barrens. It was a cold day but not too cold for a river trip (about 35 deg.). It was exquisitely beautiful and serenely quiet. Atlantic White Cedar, amazing ice formations, scent of pine and lots of tricky maneuvering around fallen trees = balm for the soul.

It's been nearly three weeks since my last post and since then most of the waterways in the Delaware River Basin have fallen to near normal levels. The NYC reservoirs were up to almost 91% capacity at the beginning of January but have fallen a bit down to 88%.

This is time of year that we begin to assess ice build-up and the amount of snow pack, usually but not always a concern specific to the Upper Delaware watershed. The winter floods and "spring freshets" can be the most destructive of the distinct flood types that occur on the Delaware River.

More on that later, but here is an interesting discussion and list of winter floods that have occurred in New Jersey courtesy of USGS.

Taking a week off for surgery and then plan to take a trip up to Narrowsburg, NY in late January for a look at the river and to do some eagle watching.

On the Rise...

Creeks in the lower Delaware River watershed are rising out of their banks with more rain to come and that speaks to the fact that they had more snow on the ground than many areas upriver from the tidal zone.

The NWS has a FLOOD WARNING issued for the Brandywine, White Clay, S. B. Rancocas, and Cooper to name just a few. The lower Neshaminy at Langhorne was surging for flood stage but that suddenly began to drop so the snow melt might be finished and the rain is beginning to taper off. The Brandywine at Chadds Ford is already approaching flood stage.

The Delaware River at Riegelsville is just beginning to rise and running above normal but not by that much. However the Lehigh River is coming up quickly and that will push the Delaware up overnight but not to 20 feet (22 feet is beginning of flood stage). Piedmont tribs like the Wickecheoke, Locatong and Tohickon are rising rapidly as well and these will impact the river below Frenchtown.

It looks like the aforementioned creeks and rivers that are subject to the flood warning will have a rough night.

Speaking of Floods...

As mentioned a few weeks back, it seems like the watershed of the Delaware River is primed for spring flooding. That was before the big nor'easter that dumped between 6 inches and 2 feet of snow. Fortunately the heavier amounts were in the lower watershed.

A lot of moisture is locked up in the landscape and the equivalent of a few inches of rain sits on the land in the form of snow.

Recipe for a Winter Flood
Ingredients: Saturated soil; generous amount of snow cover; streams running at or above normal; wetlands, ponds and reservoirs filled (to taste). Vigorously stir in a rainstorm and allow to rise overnight.

Ice Man Commeth...

I've managed to get out on the water at least once per week so far this cold water paddling season. Pine Barrens and Delaware River tributaries. It looks like more sustained cold weather is headed to the region so every day on the river is precious. The cutoff point is around 38 deg but that's with sun and no wind, and on shallower not too difficult streams to reduce chance of sustained immersion.

It's a great time of year to be on a swift moving creek.

Myth busting...

The DRBC today released its report on the role that the reservoirs played in the recent three Delaware River floods. I haven't had time to digest it but the Delaware River Basin Commission's interagency study group concluded that the reservoirs played at best, a minor roll.

Their conclusion is not news to me. I've instinctively known this to be true and have spent years gathering data and anecdotal information to help understand the issue. What has been most distressing is having to watch the myth that the floods were largely man-made and caused by mismanagement of the three drinking water supply reservoirs located in upstate New York. The "reservoirs did it" myth took root like Japanese Knotweed and become a pervasive belief among residents of the river valley. The DRBC and others did not effectively respond to the myth makers' emotional-based narrative.

This is a timely topic because now that the ground is saturated, the coming winter freeze will lock in this background condition and create a higher flood threat for 2010. Flooding along the Delaware is an infinitely complex topic. It's simple and satisfying to believe that the floods will stop if only the powers that be manage the reservoirs.

That myth is more comforting than the terrifying truth that floods are random acts of nature.

The truth is that flooding is natural, desirable and beneficial for the river and its complex ecology. Above all, flooding is inevitable. Only a fool would live on a floodplain believing they can do so without consequence, if only the reservoirs were kept below 80% capacity. Unfortunately, there are many who believe this and they are no friends of the river.

There are at least 4 distinct types of floods, each with its own set of background conditions. And that's the beginning point for the book of Delaware River floods. I can't keep my eyes open so it will have to be written another day.