Raingarden Installed at Mountain Lakes House

 One project I was able to get implemented at Mountain Lakes House in Princeton is the construction of a raingarden. I designed and located it so that it would capture runoff from the lawn, driveway and a portion of the roof. Township staff did the contouring, and planting was done by Polly Burlingham of Sigmund Garden fame, financed by a private donor.

It was particularly important to redirect runoff from the driveway down this contoured swale to the raingarden. Before, water flowed towards the foundation, which led to flooding in the basement.

Now, the runoff will have a positive effect, helping to keep the raingarden wet. A typical raingarden is designed to collect about 6 inches of water, which then infiltrates into the soil over a day or two, creating an underground reservoir of water that the wildflowers, sedges and shrubs can tap into during droughts.

Since it was installed last fall, it's still awaiting its first growing season. Plants have been labeled (cardinal flower, joe-pye-weed, winterberry, buttonbush, etc). You can reach this site by parking at the Community Park North parking lot off of Mountain Ave at 206, and walking down the long driveway through the woods to Mountain Lakes House. In the distance in the photo is the recently restored upper Mountain Lake.

Communal Bath for Robins

Flocks of robins have been appreciating the backyard minipond the last couple days, arriving in flocks of 20 or so to splash in the shallow water. Their frenzied head-dipping is reminiscent of the movement of the birds on this toy, and wooden birds are much more cooperative in front of a camera.

While half of the flock is in the water, the other half remains perched in the overhanging branches, to keep a keen eye or two out for any approaching photographers. The old apple tree next to the pond, half of its branches dead, serves this function well. The human inclination is to trim trees up and remove all the dead branches, but the birds make it clear they like lots of perches of varied heights--the better to scope out the ground before dropping in.

Princeton High School Floods Again

Yesterday, with Hurricane Irene headed our way, I stopped by the Princeton High School to check on preparations for the coming deluge. This part of the school had stormwater seep under the doors a week ago, and was most emphatically flooded two years prior when Hurricane Bill paid a visit. I've heard from several sources that the bill for Hurricane Bill included a new stage floor for the high school's performing arts center, which had become warped by flooding damage. Even if insurance paid for the replacement, one has to wonder if the district school's insurance rates took a jump afterwards.

Here's how the flooding happens: The retention basin in the photo (a.k.a. "ecolab", which we have planted with native wetland species), is surrounded on three sides by the high school and receives runoff from the high school roofs and also from nearby parking lots. The basin in turn drains into the system of stormwater pipes underneath Walnut Street. If it rains long enough and hard enough, however, the street's underground stormdrain system becomes filled to the brim, water has nowhere to go, and the basin overflows. At that point, pipes no longer matter and surface flow dictates where floodwater goes. Since water flows downhill, the only way to get rid of the water is for it to flow out to Walnut Street and safely away from the building. Unfortunately, Walnut Street is higher than the high school doorway thresholds. In these heavy rains, Walnut Street floods and becomes a river, and stormwater actually flows towards the high school rather than away.

The highschool has responded to this by placing sandbags in front of all the doorways during heavy rains. These help, but when I stopped by at 1am this morning, after Irene's fury had begun to ease, the music room and hallway into the performing arts center showed signs of having again been flooded. (These photos were taken this morning, after stormwater had receded.)

Exasperated school staff were trying to pump water out of the school. The custodians had just finished prepping all the floors for the return of students, and now they would have to do it all over again. The cafeteria had flooded, and it looked like utility rooms in the basement were now under water.

One staff member tried to blame the vegetation in the retention basin, but all around him was evidence that the vegetation had played no role in the flooding whatsoever.

 

The drain, photographed this morning, showed no signs of blockage, which is no surprise given that, when the street storm drains become overwhelmed, the water reverses flow and heads in to the retention basin from the street, rather than out.

At 1am this morning, this whole area was a lake.

A curb cut meant to carry surface water away from the retention basin was instead carrying water towards it.

The only solution I see is to lower the curb on the other side of Walnut Street so that the mighty Walnut Street River can flow into the field owned by Westminster Conservatory.

This, in fact, is what some water was doing last night, but to an insufficient extent.

A pond formed in this field last night, next to the Westminster parking lot. Last year, the field was declared by Westminster's own consultants to be a wetland that could not be developed. Since the conservatory uses the highschool performing arts center for some of its performances, utilizing this field more effectively to prevent flooding of the high school seems to be a solution that would benefit all involved.






What needs to be made clear to decision-makers is that the native plantings in the retention basin have no impact on flooding, lest this ecologically vibrant and educational planting become the victim of an invasion of red herring.

Flood Alert--Basement Recall

Heavy rains in late August can cause major mischief in Princeton, with many people gone on vacation and a lot of basements left unwatched. This is a good time to recall someone who's out of town, and consider contacting them to ask if their basement is prone to flooding. Typically, the worst flooding happens during the last of a series of downpours, after the ground has already become saturated from previous rains.

For my part, as the last downpour was easing up at dusk, I headed out across flooded streets to the high school ecolab wetland, where past overwhelmings of the stormdrains had caused water on Walnut Street to flow under the back doorway into the performing arts center, ruining the stage floor. Since that fiasco, the school has sandbagged the doorway during heavy rains. But in late August, it's quite possible that the staff who know about the sandbagging procedure are on vacation.

 

The first evidence of heavy flooding was a green frog playing the role of refugee from its own wetland,

which was filled to the brim with water from nearby roofs, parking lots and streets. It's supposed to fill up like that; the design flaw is in the overflow, which sends extra water not out into the street but instead towards the school. The hallway of the performing arts center looked a little wet. I slogged home, called the borough police and asked them to have someone at the school check for flooding indoors.

Of course, it would be nice if product recalls could include flood-prone buildings and basements. Simply send them all back to the original builders for a redesigned version.

Harrison Street Raingarden in July

Another sight to be seen from Hamilton Avenue is the raingarden at Spruce Circle, just up from the intersection of Hamilton and Harrison Street. Type "raingarden" into the search box at the upper left of this blog and you'll find posts showing the raingarden in various seasons.

In July, the switchgrass (foreground) is fully grown, and the JoePyeWeed is in full flower (tall and purple).

A view uphill from the raingarden shows the long roof that feeds the garden during rains.

Here's a view from uphill looking down. Rain flows through the downspouts and out onto the grass, then down to the raingarden, where it collects and infiltrates into the ground over the next 24 hours or so, creating a nice underground reservoir of moisture to feed the roots of the wildflowers through droughts. Only in the most extreme droughts, such as the two-month long drought last year, does watering prove necessary.

Scattered through town, taking advantage of wet, sunny spots, raingardens like this one serve as lifelines for pollinators otherwise starved by the trees n' turf landscaping dictated by convention.

Diverting a Neighbor's Runoff Away From the House

During heavy downpours like yesterday's, water from my neighbor's driveway used to head straight for my house. This flow of water from one property into another is a common source of tension between neighbors.

Rather than complain, I dumped some extra dirt under some bushes on that side of my yard, forming a berm that redirects the neighbor's water towards the front of my lot. The water flows into a raingarden under the dogwood tree, where a buried, perforated pipe carries any unabsorbed water out to the sidewalk.

It's subtle, but you may be able to see the water flowing across the sidewalk into the row of hostas.

The goals here are 1) divert water away from my foundation, to reduce humidity in the basement, 2) capture some runoff in a raingarden so it has time to infiltrate into the ground to feed the trees, 3) use the city stormwater system in the street as an escape valve for any extra water the raingarden can't hold.

The only drawback is that, if you want to have the satisfaction of seeing that the system works, you have to go out in the rain, which, after the lightning and thunder has passed over, may not feel like a drawback at all.

Early Summer Wildflowers

A nice native combination this time of year is black-eyed susan in front of bottlebrush grass. These, along with cutleaf coneflower, tall meadow rue, wild senna and other local natives, I included in a miniature raingarden planting along the sidewalk at Whole Earth Center on Nassau Street.

Some white flowers to keep an eye out for are bottlebrush buckeye (in front of Mountain Lakes House),

buttonbush (along the edge of Carnegie Lake and the canal),

and Lizard's Tail (also found along the edge of Carnegie Lake).

A Manmade Wildlife Sanctuary on Walnut Street

 One of my favorite spots to stop on a summer evening is the ecolab wetland at Princeton High School. Most detention basins are mowed, making for curious grass pits of little use for wildlife, but this one we managed to transform into a glorious display of native plants, teaming with frogs, crayfish and birds.

The basin was designed to receive water from the highschool's roofs and a parking lot or two, but the unusual plant diversity is sustained by the high school's sump pump. "Old Faithful", I call it, because it pumps water from the basement year round, every fifteen minutes or so.

The biggest threat to the wetland, other than loss of that wonderfully consistent water source, may come as a surprise. The weeded out plant debris in the foreground of the photo is cattail, which is the native plant people most commonly associate with wetlands. Yet, it is so aggressive that, if we were to allow it to grow here, it would soon dominate to the exclusion of 20 or 30 other native species.

Liking cattails, we allow them to grow in one corner,

and also planted a less aggressive species of cattail--narrow-leaved cattail, which is also native but rarely encountered in the wild.

Stop by sometime when you're on Walnut Street, on the back side of the school. It can be fun to watch the goldfinches and sparrows bomb around, ducking into the cover of a willow, eating seeds, feeding their fledglings and singing their proud songs atop last year's dried stalks of hibiscus.

Gravity Plus Rainwater= Backyard Waterfall

Garrison Keillor  made a disparaging remark about drainage during his show at McCarter Theater this past winter, but for many Princetonians, what seems like a mundane subject can raise considerable passion, particularly when the runoff is coming from the neighbor just up the hill, or results in basement flooding.

My advice is to give the water a good ride through the yard. Don't spurn it, or consign it to underground pipes. Water can be mischievous, but its obedience to gravity is absolute. Herded away from the foundation, it can flow on the surface to make attractive ephemeral streams and waterfalls, and feed plantings.

There's no reason, for instance, why water must fall from roof gutters in the obscure confines of a downspout. In this project, water emerges from a gutter (obscured by the shrub) in a small waterfall that is carried away from the house on a rockstrewn "streambed" underlain by black plastic.

The roof runoff flows down the rocks some 20 feet into a small raingarden (not in photo), where it collects and seeps into the ground, feeding nearby trees and any roots that reach it from the vegetable garden. In a deluge, the raingarden in turn overflows onto the lawn, where the water continues downhill as sheetflow. Whatever doesn't get absorbed eventually flows between the two neighboring houses down the slope and into a storm drain.

Spring Cleaning in the Raingarden

 One of the easiest and most rewarding spring tasks is preparing a raingarden for a new season of growth. This raingarden was installed by Curtis Helm and me at Princeton borough's Senior Resource Center on Harrison Street. Water from the roofs is channeled into the garden, where it accumulates to several inches in the hollowed out area and then slowly seeps into the ground. Mosquitoes are not an issue because the water does not stand long enough for them to breed. A list of the plants, all adapted to wet soils, can be found in another post.

All that was needed was a pair of pruning shears, gloves, and a plastic grocery bag that was conveniently found amongst all the paper and plastic trash caught by the raingarden over the winter.  

 Though the spring cleaning of a raingarden is easy and rewarding, I nonetheless postponed it until the last minute. One more week and the new growth would have become tangled in last year's dead stalks.

First step was to cut the brown stems of joepyeweed, green bulrush and other native perennials.

 It's important to check the downspouts that conduct water to the garden,

one of which had lost its underlying stones and needed a little tightening of the joints.

Pulling the occasional weed like false strawberry (Duchesnia indica, also called Indian strawberry, because it is native to India),

and gill-over-the-ground ( Glechoma hederacea, also called creeping charlie, or ground ivy) is a piece of cake if the soil is still soft after recent rains. 

Garlic mustard is a common weed that will spread by seed if not pulled out before it flowers. I've heard it makes good pesto, but have never tried it out.

 All that was left was to pick up the trash and toss the stalks back in the woods. No need to burden the borough crews with yardwaste that can easily decompose unnoticed back near a fenceline.

Less than an hour and it was done. Now to figure out how to make a raingarden grow cake.

Plant Rescue at Mountain Lakes

Now, that's strange. Seems to me there was a lake around here somewhere. The plug has been pulled, the 7 feet of fertile sediment accumulated over the past 100 years is being dug and hauled off to farms and topsoil makers, and the dam is being restored to its cerca 1900 appearance. Given the highly conducive weather thus far, the contractor is hoping to complete restoration of the upper lake and dam by December.

One of the streams that feeds the lakes enters back where the trees meet the mud in this photo, between the two backhoes. From an old aerial photo the engineers determined that the pond used to extend further up into that valley, and I was alerted that some more mud and associated plants would be coming out.

FOPOS board member Tim Patrick-Miller agreed to help me rescue some of the wetland species before the digging started. Much to my surprise, we found 4 species to add to the list of plants growing at Mountain Lakes.

In the wheelbarrow (our manual labors contrasted comically with the big machinery of the dredging operation) is pickerel weed, which is rarely found growing in the wild in Princeton. It likes shallow standing water at pond's edge.

Nearby was a little gravel streambed, away from the main current, that was clearly perfect habitat for three other species of plants also rarely encountered. This one, new to me, turned out to be ditch stonecrop. Not a pretty name, but it's true it was growing in something akin to a stony ditch.

Water plantain has oval leaves and tiny white flowers. It also needs a very stable hydrology, quickly perishing for lack of water.

Petals and branchings come in threes.

Bur Reed has leaves like an iris and seed capsules like those that fall from a sweet gum tree.

All four of these species only survive in locations that stay consistently wet throughout the summer. Though this continent once had abundant wetlands with much more stable hydrology, suggesting these plants were once abundant, the only places I find them now are in areas kept artificially wet, such as the edges of impoundments like Mountain Lakes, and the pump-enhanced marsh at Rogers Refuge.

Two New Grasses Bloom at the High School

A few years back, I spent an afternoon with some of Tim Anderson's science students collecting bags of Indian grass seed in a location where annual mowing allows prairie species to survive. This is the same Indian grass that flourishes in tallgrass prairies out west. In Princeton, it's most common along the petroleum pipeline right of way that cuts across the Princeton ridge, and in the meadows at Tusculum. Tim wanted to get some growing in the high school ecolab wetland on Walnut Street.

This is the first year they have grown up and flowered in significant numbers on some of the higher ground at the high school wetland. They have golden anthers that can be attractive in a subtle, hard-to-photograph sort of way.

Another grass at the wetland, planted this spring and now flowering, is wild rice, which grows wild along the Stony Brook and at Rogers Refuge. Like corn, it's an annual that grows to remarkable size in one season. The wild rice, when combined with the cattails, Jerusalem artichoke, duck potato, elderberries and, for carnivores, the thriving crawdad population, is making the wetland look more edible all the time. This photo reproduces exactly what the flower head looks like when I have my glasses off.

Duck potato,a.k.a. arrowhead, is also blooming this time of year,

along with mistflower (Eupatorium coelestinum), which only grows to two feet high. It's ambitions are more horizontal than vertical, as it can get expansive and pushy if not surrounded by equally aggressive natives.

Cardinal flower (red) and boneset (white) are likely no longer blooming when this is finally posted. If you visit the wetland now, the dominant color may be yellow, with tickseed sunflower and the native tuberous sunflower called "jerusalem artichoke" taking over the stage.