Thursday, September 22, 2011

PWC Rain Garden Survives Hurricane Irene!

Well - Hurricane Irene certainly produced lots of stormwater for us to observe! A quick look at the USGS gage at Graterford illustrates how quickly Irene poured through the valley and the amount of water that followed with Hurricane Lee. Many felt like we had been hit with twin tsunamis!

Given the amount of water passing through the watershed and the rate at which the Perkiomen rose, we were happy to learn that there were few local injuries resulting from the flooding. One of the primary reasons we did not have more damage was the large areas of preserved and undeveloped  floodplains that exist throughout the watershed! It is great that we are talking about rain gardens and rain gardens will do their part to help reduce flood waters but maintaining undeveloped and naturally vegetated floodplains for all creeks, large or small, is a critical action that communities can take to protect themselves against flooding. Levees, dams and floodwalls may protect limited areas but they do not reduce flood volumes and only serve to push floodwater elsewhere. Floodplains on the other hand, allow flood waters to spread out, slow down and begin soaking onto the ground.

Irene came blowing through the Perkiomen Valley late on Saturday, August 27. By Sunday morning, the PWC headquarters in Schwenksville had become an island! We were surrounded by a brown, raging Perkiomen Creek that infiltrated our building as well as the brand new rain garden. Records indicate that our stone bank barn was probably in place as early as the mid 1800's and was part of larger operations associated with the Pennypacker Mills conplex and the mill that once stood in Red Fox Park. Because it was originally a barn, flooding was probably not considered too much of a problem. (The photo below was taken from the middle of the Rt 73 bridge over the Perkiomen at Schwenksville, looking toward Skippack. )

Well, times have changed and so has the expectation of high water conditions associated with our changing climate. A Union of Concerned Scientists Report for Pennsylvania ( suggests that we can expect more storms like Irene in the coming years. These larger, more dramatic storms will interrupt longer periods of drought-like conditions and extremely high temperatures. Sounds an awfully lot like most of 2011 so far!

The one bit of good news for the PWC was that our brand new rain garden was not damaged. The photo below was taken Monday morning, August 29, after much of the floodwater had receded. We do not think the rain garden was totally under water but we could tell that lots of water had passed through the area or had swirled around close to the garden during the storm. But it had absorbed a great deal, the plants were all still in place and there was no standing water by Monday. Pretty amazing!

The PWC is still catching up on our regular work as we clean-up and plan for repairs at our headquarters so we hope to get back to the blog with more details about planning your rain garden project before long. Please check back soon for the details.

In the meantime, contact your local municipal offices to learn about your local floodplain regulations. Municipalities should have floodplain maps on hand and should be able to tell you about the ordinances controlling what can be constructed in a designated floodplain. Development within the floodplain is controlled at the municipal level so it is up to all of us to make sure our elected officials take precautions to keep floodplains clear of structures and naturally vegetated. The two photos below are of the large floodplain at the Graterford bridge in Perkiomen Township. The Creek is actually behind the photographer! Imagine if condos or a shopping center had been constructed in that meadow.

Instead of more flood damage, this floodplain allowed large volumes of water to spread out and slow down, possibly saving structures and people downstream. We will need more open spaces like these, in addition to more rain gardens and bioswales, to accomodate the changing conditions coming our way.

We will be back soon with details about planning your rain garden - stay dry!

Friday, July 29, 2011

Perkiomen Watershed Conservancy's First Rain Garden Takes Shape

Greetings and welcome to the third posting by the PWC about our rain gardening efforts.

If you have been following along, you know that the PWC has been working with local communities to help them meet the Municipal Separate Storm Sewer System (MS4) regulations that have been enacted by the Pennsylvania Department of Environmental Protection. All 50 states are enacting similar regulations aimed at protecting national water resources.

In past posts, we have discussed how important it is to treat our rainwater with a little more respect! Noting that rainwater is the only water available to replenish local ground water supplies. Local water supplies can become stressed as our communities draw more and more water from local wells. So it is vitally important that we give our rainwater a chance to infiltrate into the ground and down to the water table, or aquifer, below. Many older, shallower wells have gone dry as communities have expanded, drilling more wells and stressing localized water supplies.

In addition to our personal water supplies, groundwater supplies water to creeks and streams during periods of low rain fall or drought. As the water table is lowered, streams can loose this water supply from underground seeps and springs, leaving some stream sections high and dry. As streams dry up, the wildlife they harbor either leaves for a better location or simply dies.

These issues would be significant enough to prompt us to take actions to protect our water supplies but it may be even more critical as climate changes continue to impact our region. The Union of Concerned Scientists (UCS) has completed an evaluation of climate issues specific to Pennsylvania.
The report indicates that we can expect more periods of prolonged dry spells puncutated by more severe storms.

Given that we have been struggling through one of the hottest, driest summers on record with rain fall still at about 50% of normal volumes, the UCS's prediction seems eerily accurate. As we all know from experience, once the soils dry out, they become hard and impervious, requiring a long, slow, steady rain that can slowly soak in and loosen dry soils. If we can expect more intense rain storms going forward, it will become more and more important for us to provide areas where rain can be absorbed and allowed to infiltrate deeper into the ground rather than flowing overland directly into local creeks and streams.

Rain gardens are a simple way to provide a path for infiltration of rainwater in the midst of our hardened landscapes. The PWC has received some grant funds from the PADEP to install two rain gardens and a cistern to enhance stormwater management at our headquarters in Schwenksville. Attached are a few photos that show the construction of garden #1 adjacent to our parking lot. You will notice that our garden has no plants in it - yet. That is because the PWC's interns and Conservation Coordinator constructed the garden in 98 degree heat with no rain forecast. So rather than torture our new garden plants, we are waiting for better, wetter conditions.
A composted soil mix was purchased to ensure that infiltration would be possible and to provide better conditions for the new plants.
 The test hole is well-drained! 98 degrees in the shade helps evapo-transpire a lot of water!

 Using the Toro Dingo to remove sod and break up the soil.

It is important that the rain garden be level so that the water does not run through before it has time to infiltrate into the ground.

 Our hardy interns worked in extreme heat to excavate and level the rain garden in preparation for the Rain Garden Workshop held July 20. What a great group of hardworking and dedicated young students! Thank you for your amazing efforts!

 Workshop attendees put the final stones in place for the retaining wall. Plants will be added later once the extreme heat wave ends and rain returns to the Perkiomen Valley.

All finished - for now. The new rain garden will help drain standing water from our driveway and parking lot areas and help infiltrate it into the local groundwater supplies. One small step toward cleaner water and healthier environment.

The PWC rain garden is a large project, certainly larger than most homeowners would need to infiltrate rain from their downspouts.  Our next blog will address how to decide on the size and location of your rain garden.

Please feel free to comment on our blog or contact the PWC if you have questions about stormwater and ways to keep our water supplies clean and abundant. We can be reached at 610.287.9383.

Wednesday, May 11, 2011

So what is a Rain Garden anyway? Post 11.1

Welcome to the Perkiomen Watershed Conservancy’s Rain Garden blog. In our first article, we discussed why it is so important for all of us to be mindful of our stormwater management methods and for each of us to find ways to slow the flow of stormwater so more of it can soak into the ground and recharge local water supplies. We are losing a valuable resource when we flush our stormwater quickly into local streams and damaging critical aquatic resources in the process.

So how do we slow the release of stormwater without having our properties become a quagmire of soggy soils? Since the title of our blog is Rain Gardens, why don’t we start there!

The term “rain garden” can be slightly misleading, conjuring up images of watery gardens or soggy wetlands but really the term relates to the rain or stormwater that the garden is designed to absorb. A more accurate name for this garden might be a stormwater garden, but that sure doesn't roll off the tongue so easily.

Rain gardens have a very specific function and need to be constructed with this function in mind. The well-designed rain garden will collect, store and drain stormwater runoff, allowing the water to slowly infiltrate into the ground where it will be cleaned by the soil and help recharge local groundwater supplies. (Just a note – the natural ability of soils to mechanically, biologically and chemically clean water is well known. However, it is the slow movement of the water through this amazing natural system that allows the cleaning actions to occur. So slowing down the flow of stormwater is critical to reducing stormwater damage as well as recharging our local water supplies.)

Rain gardens mimic the natural functions of upland forests and meadows. The vegetation and shape of the garden help slow the flow of stormwater. The bowl-shaped depression of the rain garden is similar to the many small depressions and undulations of the natural landscape that allow rain water to stand long enough to slowly soak into the ground. And the specific soil mixtures of a rain garden help rainwater infiltrate through the soils to be filtered and cleaned. 

Once completed though, you may not notice much difference between a rain garden and other gardens except than one is a recessed, shallow bowl while a regular garden is often a molded, raised bed. But there are three unique components of rain gardens that must be considered during the initial construction.

1.      Each rain garden must have a defined entrance area where the water drains into the garden. This can be a pipe or downspout or a shallow swale that leads to the main part of the garden.
2.      The main feature of the garden is the recessed planting bed, which should be flat and level throughout.
3. A mounded berm around the three downhill sides the garden with level edges and even height allows the water to be retained in the garden area until it is absorbed.  The berm will be highest on the downhill side tapering off as it meets with the uphill side of the garden. Depending on the slope of the area the berm may be small or large.

Planning is imperative in order to create a properly functioning rain garden. Soil conditions, the amount of sunlight and the size of the drainage area will guide your garden planning. These issues will be addressed in the next Perkiomen Rain Garden Blog. To get a head start, make some notes about how much sun or shade your potential rain garden will receive. If you are feeling energetic, you can do a percolation test, or perc test, to see how fast your soils drain. Start by digging a small hole about 3 foot deep. Fill the hole with water and let the hose run for a few minutes after the hole is full. Then see how long it takes for the water to drain away. The faster the water drains, the better the test results.

The Conservancy is a private non-profit organization established to conserve and protect the land & water resources of the Perkiomen Creek watershed. We are located in Schwenksville, PA but work throughout the Perkiomen Creek's 362 square mile watershed. We are committed to excellent environmental education and practical, effective, hands-on conservation and stewardship efforts aimed at improving water quality and aquatic habitats.

The Conservancy is also a founding member of the Perkiomen MS4 Partnership whose goal is to help member municipalities address the public awareness and participation requirements of the PaDEP and US EPA's Municipal Separate Storm Sewer System (MS4) programs. The overall goal of this blog will be to provide general information about stormwater issues and specific information about rain gardens. We hope you will follow us as we explore these interesting and important topics with our communities.

Friday, April 8, 2011

Rain Gardens, Stormwater and the Perkiomen Watershed Conservancy Post '11.0

Greetings and welcome to a new blog
by the Perkiomen Watershed Conservancy.

The Conservancy is a private non-profit established to conserve and protect the land & water resources of the Perkiomen Creek watershed. We are located in Schwenksville, PA but work throughout the Perkiomen Creek's 362 square mile watershed. We are committed to excellent environmental education and practical, effective, hands-on conservation and stewardship efforts aimed at improving water quality and aquatic habitats.

The Conservancy is also a founding member of the Perkiomen MS4 Partnership whose goal is to help member municipalities address the public awareness and participation requirements of the PaDEP and US EPA's Municipal Separate Storm Sewer System (MS4) programs. The overall goal of this blog will be to provide general information about stormwater issues and specific information about raingardens. We hope you will join us as we explore these interesting and important topics with our communities.

First a few words about stormwater and why we care so much about all that water falling from the sky!

Stormwater refers to rain, whether it drizzles less than an inch throughout the day or comes as a downpour dropping an inch or more an hour, as well as water from melting snow. All of our precipitation is critical to keeping local water supplies clean & fresh as well as available to the many communities, businesses and homes that rely on the Perky and its associated groundwater resources for day-to-day water supplies. Over the many years that communities and state agencies have been trying to manage stormwater damage, we have learned a great deal about what is effective stormwater control and what has just not worked.

One of the most important findings is this: as we have collected and flushed stormwater through pipes and basins, we have seriously short-changed our local water supplies and are actually increasing the stormwater impacts to our creeks, streams and rivers. The principal problem with past designs has been the speed with which we try to remove rainwater from our communities.

By collecting stormwater in detention basins - those large bombcrater looking depressions - we increase the volume of stormwater being discharged to creeks and we increase the velocity and power of those discharges. More water moving at greater speeds has more power to erode stream banks, carry more pollution into even very small creeks, and obliterate aquatic habitats with sediments. Under more natural conditions, much of the 43 or so inches of precipitation we receive locally each year, would infiltrate into the ground, becoming part of the local ground water supply. Twenty years or more of diverting that rainfall directly to local creeks has led to receding ground water levels and hundreds of emergency well drilling permits for wells that mysteriously go dry.

So regulations have been changed to help communities get more of their precious stormwater into the ground rather than directly into local creeks. By infiltrating more stormwater, we can recharge our groundwater supplies, reduce overall pollution and erosion within our beautiful creeks and help ensure that groundwater supplies will be sufficient to outlast periodic droughts. 

As we move forward with this blog, we will expand on stormwater concerns, provide some great options that even small property owners can implement and help all of our Perkiomen communities improve and protect our local water resources. One of our goals is to help propoerty owners implement hundreds of small rain gardens throughout the watershed. We hope you will check in with us often and share this site with other concerned commuity members.

You can send comments or questions to  Please note"Stormwater" in the subject line. We will do our best to answer your stormwater questions and provide practical options for addressing stormwater concerns.

To learn more about the Perkiomen Watershed Conservancy, join us on Facebook or visit