Pond Removal/Stream Restoration

Pond Removal/Stream Restoration

A few years back, DL Howell designed a subdivision that involved the removal of an old farm pond and restoring the original spring fed channel. While many of us think ponds are a good thing… I mean, who doesn’t love a good game of pond hockey in January or sitting along the banks in the summer with a fishing line out, but surprisingly they can actually be damaging to the environment. Yes, they do provide a great place for wildlife to live, but in reality a large shallow pond can also be very detrimental to the downstream microfauna and fish habitat as they increase the water temperature and can harmfully affect the aquatic ecosystem. The Department of Environmental Protection also looks negatively at in-line ponds as they block fish from moving freely up and down the creek. So needless to say, it wasn’t that difficult to obtain the necessary approvals from the DEP and Army Corp to draw down the water, breach the berm of the pond, and restore the channel to its original condition. After the initial work was complete, riparian buffers were implemented by planting natives species along the newly formed channel, which will provide for new wildlife habitat and water quality filtering.

Take a look at these before and after pictures…

 

 

Call Before You Dig!

Call Before You Dig!

PA One Call, Pennsylvania 811, Act 287. The program has several names but one main purpose – to prevent you from hitting an underground utility line during construction activities. You might be thinking it’s no big deal if a cable TV line gets cut, but I think we can all imagine how bad it could be if you put a shovel through a 16” gas pipeline. If you check the PA One Call website, they define themselves as “a service company dedicated to minimizing utility service interruptions, reducing on-the-job injuries and deaths, promoting a higher level of public safety and protecting the environment.” The program was developed in 1972 and over the years it has evolved from phone, to phone & fax, to the current phone & online (web ticket) system. The advancing technology has really helped the program grow. In the first year of the program only 389 location requests were submitted. In 2019, the PA One Call system responded to 1,037,463 location requests, which works out to over 2,800 requests a day, or just about 2 requests every minute.

The program started out with a simple concept – call before you dig. A phone service was set up and linked to utility companies. If you were digging in an area, you call the number and let them know where you are. The program will then contact local utility companies to see if they have any service lines in the project area. If the utility company has service lines in your project area, they will provide you with location information. If your project is in the design phase often times you will receive copies of plans indicating the location of the utility lines. If you are actively digging, the utility company has 72 hours to field locate their underground utilities, usually with paint or flags. The PA One Call system also provides contact information for utilities in the area even if they are not currently located on site. It is a great point of contact if you need to extend public utilities to your project.

The PA One Call system has tremendously improved our ability to see potential utility conflicts before they happen and plan around them before construction begins. As civil engineers, this is a helpful tool in our world of design. Don’t hesitate to reach out to DLH for all your design needs, and don’t forget to call before you dig!

The Dwindling Supply of Plastic

The Dwindling Supply of Plastic

As most of us know, businesses will keep enough products stocked to meet the daily demand of their consumers, but what happens when that demand suddenly increases exponentially overnight. You probably already know the answer, prices go up, availability is near non-existent, and orders can start to take weeks to fill. Most businesses and developers are currently feeling that in a big way with one material in particular: plastic. Plastic is used in an extraordinarily large number of items that we use every day, from food and beverage containers and medicine bottles to storm drainage pipes, DIY supplies for those working on projects at the house, and consumer electronics.

This reduced supply stems from back at the beginning of 2020 when Covid first spread across the US. Workers and refineries were either forced to close down or work at a reduced capacity, while shipping companies that supply the raw materials for plastics were forced to do the same due to the lockdown. At the same time, demand for these materials increased drastically to the point that demand exceeded supply, and existing stockpiles of the materials were expended. Supply suffered further delays in production when winter storm Uri hit Texas and Louisiana, two states which contain a majority of the processing plants required to make plastic. Utility infrastructure in both states suffered widespread damage due to the deep freeze furthering the deficit. Production at these facilities is slowly starting to ramp back up, but it will be a while before they are back at 100%.

Another side effect of Covid on the plastic industry is the increased demand for single-use plastic cups and masks. While these products help to prevent the spread, people have the habit of discarding these wherever they feel. A good practice to keep is to limit the use of one-time items as much as possible to reduce their future impact on the environment.

Fortunately, production at the plants has resumed, and those much-needed materials are starting to be produced and shipped to those who need them, and much like Covid, the raw material deficit will pass.

What a difference a ZERO can make!

What a difference a ZERO can make!

The 100-year storm sounds like a storm you may only need to worry about once in a lifetime unless you are really “lucky” and get to see it twice. Lately, it seems we get to witness one nearly every year or so with its little brothers, the 25 yr and 50 yr storms popping up every summer. And with each big flooding event comes the phone calls about neighbors flooding out neighbors because someone put in a pool or added a shed. Our local politicians slide into their all too comfortable “reactive” (rarely proactive) roles and start trying to do something “so this never happens again.” Truly my all-time favorite statement to hear them say is, “we are going to come together in a bipartisan way to enact legislation to ensure this never happens again.” #hugeyawn And when they follow that up saying they are going to “raise awareness” to an issue we all deal with on a daily basis I get all tingly. Sprinkled, however, into the phone calls about flooding are calls ridiculing us engineers on why all of our fancy-dancy and expensive stormwater designs aren’t “working”. This is easily taken in stride if you understand stormwater runoff and how things are modeled. In short, other than the toddler of storm events, the two-year storm, the other storms have ZERO volume reduction occurring when they pass through the previously aforementioned fancy-dancy and expensive stormwater management facilities. You heard that right; VOLUME IS NOT CONTROLLED!

Therefore, you are right. If your neighbor added a pool or a shed or a 100 lot subdivision upstream of you, then you, in fact, are seeing MORE runoff every time it rains. Period end of story. More impervious equals more volume of runoff. The more it rains, the more water there is to runoff. Now, theoretically, the RATE of runoff is less, but that is for another newsletter one day. I think we can all agree that when you are part of the misfortunate that live/work at the bottom of a large watershed, that volume of runoff becomes the main concern. There is just nowhere for the water to go except up, and hence flooding occurs. None of this should really be news to any of us. However, one thing Tropical Depression Ida has done is turned up the candle power on the spotlight shining on these rainfall amounts. Engineers model for the 24-hour storm event, meaning we calculate runoff assuming a certain number of inches of rain falls during a 24 hour period. But the problem is we are getting these rainfall amounts over a much shorter time period, and when you get more rain in a shorter time period, that is bad. For example…7.2 inches of rain in a 24 hour period has a return frequency of 100 years; however, 7.2 inches of rain in a 6 hour period has a return frequency of 1,000 years!! The West Branch of the Brandywine Creek received just that during Ida and flooded large sections of Coatesville. The question now is….how will our local governments react to “make sure this never happens again”? Will the 100-year storm be redefined? Will we be required to design for the 1,000-year storm? That all remains to be seen but rest assured when it changes, D.L. Howell will be ready to design a system to “make sure this never happens again!!!”

Record-Breaking Hurricane Ida

Record-Breaking Hurricane Ida

Not all rain events are created equal! Last week, Hurricane Ida slammed our area with unprecedented rains. For those who live along any of the major creeks in Chester County or other low-lying areas, the flooding was unlike anything we have ever seen. With rain intensities north of 3’’/hour in some locations, areas that you wouldn’t even think were at risk of flooding were either underwater or turned into raging rivers. This area has not seen such rain totals and/or such far-reaching floodwaters since Hurricane Floyd in 1999.

The severity of flooding has a lot more to do with the rain “intensity” than the rain totals. During Hurricane Floyd, areas around us saw 8 to 9 inches of rain, which was very similar to this last storm. The difference this time was that the bulk of that rain fell in just 4 or 5 hours as opposed to 6 to 8 hours, which was the case with Floyd. Because the “intensity” of the rain was so much greater with Ida, we had flood heights that smashed the previous records, some of which have stood for over 100 years.

Here are just a few of the record-breaking examples. A height of 19.1 feet was recorded along the Brandywine (south of D-town). That was 4.3 feet higher than the previous record and so high that the monitoring station itself was underwater. Some other record heights set along the Brandywine Creek were in Modena, where it topped 13.4 feet (0.9 feet above the previous record), and in Chadds Ford, which peaked just above 21’ (3.9 feet above the previous record). Unfortunately, it is cost-prohibitive to design and build for such unprecedented conditions, and we can only hope this will be a “once in a lifetime” event.

 

Privileged with Precision

Privileged with Precision

The word “privilege” is a term often heard that refers to an advantage or benefit enjoyed by a particular person or group of people.  

As I sit in my computer chair, analyzing a client’s property that contains a high-resolution drone image combined with a lidar point cloud surface, I feel very privileged to create plans in our current land surveying profession.    

Our company prides itself on learning and utilizing the newest and most accurate technology in the land surveying profession. Recently we have had the privilege of acquiring a large DJI Matrice 300 RTK drone carrying a LIDAR sensor that allows us to quickly collect field data with precision limits right around 4 inches horizontally and 2 inches vertically. This advantage can greatly decrease the amount of time we have field crews on-site and allows more time for drafters to complete a project in the office. This is quite remarkable, knowing that only a few decades ago, things were not quite the same.

It was not long ago that we had the painstaking days of recording every shot in field books. This required the note-taker to write down for every point:

  • the point’s number; 
  • the point’s description; 
  • the horizontal angle read on the transit;  
  • the vertical angle read on the transit; 
  • the slope distance from the transit to the point which was measured with either a steel tape, or by stadia; 

On an exceptionally good day, a crew might record 200 shots. God help the note-taker who didn’t bring an extra pencil in case he dropped the first one!

This doesn’t sound too bad until you realize some sites require thousands of field points. Back in the office, the surveyors then had to reduce the notes and apply the laws of trigonometry to calculate the horizontal distance, vertical distance, and subsequent elevation of each point. These points were then hand plotted on a large sheet of paper using a protractor and a scale.

These days, more and more data can be collected using this modern technology. The new LIDAR system collects 80 pulses per square meter without a single person laying a foot on the ground. This is not completely true, but this new equipment’s precision and time-saving benefit give us an advantage over our competitors.