2009 PSLS Conference Highlights

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The annual Pennsylvania Society of Land Surveyors’ (PSLS) Conference took place January 25-28 at Hershey Lodge, Hershey, Pa.

Hundreds of surveyors from across the commonwealth took part in a selection of 50 workshops that offered Professional Development Hours, and beneficial information about the latest techniques and advances in the surveying industry. At-tendees also immersed themselves in the opportunity to net-work with colleagues and vendors during the four-day event.

Some popular conference staples included the plat competi-tion, the silent auction, and the bookstore. In addition, exhibi-tors featuring the latest surveying equipment and products drew visitors throughout the day.

This year’s special guest speaker was Thomas Jefferson (por-trayed by Patrick Lee, Ashland, Mo.) who traveled through time to share words of wisdom with his fellow surveyors.

Look for more about conference highlights and photos throughout this newsletter! You might even spy your photo.

ExhibitorsPresident’s Message Conference PhotosRamblings by ChuckSurveyor of the YearUnsung HeroesChapter NewsStormwater Detention

Inside2368

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Pennsylvania Society of Land Surveyors News

Surveyor of the Year Bob Miller celebrates with his wife, Diane.

Past President Emil Bove hands the gavel to 2009 President Rick Phillips.

Patrick Lee portrays Thomas Jefferson.

OfficersRichard L. Phillips, PLS, PresidentWilliam L. Lehman, PLS, President-ElectDavid H. Artman, PLS, Vice PresidentThomas J. Morganelli, PLS, SecretaryByron W. Rimmer, PLS, TreasurerEmil A. Bove, PLS, Past PresidentRobert R. Miller, PLS, NSPS Governor

State DirectorsAllegheny Heartlands ChapterGerald L. Pastva, PLS & Norman S. Van Why, PLSBucks ChapterDonald E. Rife, PLS & Adam Crews, PLSDelaware Valley ChapterThomas Phillips, PLS & Karl E. Kreigh, PLSHarrisburg ChapterThomas W. Kimmel, PLS & Milton H. Davis, PLSLaurel Highlands ChapterRichard R. Bourg Jr., PLS & Charles L. Zelenak Jr., PLSLehigh Valley ChapterWilliam J. Beitler, PLS & Allison Bradbury, PLSMid-State ChapterFred M. Henry, PLS & Charles M. Colony, PE, PLSNorth Central ChapterJames E. Pahel, PLS & Charles G. Lang, PLSNortheast ChapterBrent L. Birth, PLS & J. Frederick Friden, PE, PLSNorthwest ChapterJeffrey P. Gilmore, PLS & Edward E. Northrop, PLSPocono ChapterStephen E. Lesher, PLS & Paul A. Waters, PLSReading ChapterJohn G. Fuehrer II, PE, PLS & Merlyn J. Jenkins, PLSSouth Central ChapterL. Bradley Foltz, PLS & Thomas Farcht Jr., PLSSouth Pocono ChapterLawrence R. Bailey, PLSSouthwest ChapterNorm J. Landsperger, PLS & Kevin P. Hannegan, PLSSusquehanna ChapterPeter J. Uhl, PLS & Frederick J. Rankinen, PLS

PSLS StaffAndrew J. Hilt, Executive Vice PresidentShari L. Taylor, Assistant Executive DirectorKate C. Sherman, Director of Communications/ Member ServicesLaurie L. Troutman, Administrative Assistant

The Pennsylvania Surveyor is published quarterly by the Pennsylvania Society of Land Surveyors (PSLS). Ar-ticles or opinions expressed in this publication do not necessarily reflect the viewpoints of PSLS, but are pub-lished as a service to its members, the general public, and for the betterment of the surveying profession. Ar-ticles may be reprinted with due credit given.

We welcome submissions via e-mail in MS Word format. Please forward to ksherman@psls.org or call 717.540.6811.

Pennsylvania Society of Land Surveyors2040 Linglestown Road, Suite 200

Harrisburg, PA 17110 P: 717.540.6811 F: 717.540.6815

www.psls.org

Thank-You to Our Exhibitors

Pennsylvania Society of Land Surveyors

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Aerocon Photogrammetric Services, Inc. Aero-Metric/Air SurveyAFLAC Atlantis Aerial Survey Co., Inc.Axis Geospatial Boyd Instrument & Supply Co., Inc.Caron/East, Inc. Cooper Aerial Surveys Co.First PointKeddal Aerial Mapping Keystone Precision Instruments Klein Agency, LLCLand & Mapping ServicesLeica Geosystems, Inc. Marquis Agency Nor East Mapping, Inc. Penn College of Technology Penn State Consultants-Surveyors Mart Penn State Wilkes-Barre Pennsylvania One Call System, Inc.Precision Laser & Instrument, Inc.PSLS Conference Raffle & Auction SECO Manufacturing, Inc.Smart Vent Spotts, Stevens and McCoy, Inc.

PSLS extends appreciation to these companies that ex-hibited at the 2009 PSLS conference:

2009 PSLS Conference photos by Cory Martin, Martin’s Studio of Photography, Ephrata, Pa.

And Now...A Word from Our PresidentRichard L. Phillips, PLS

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Continued on Page 4

One of my goals this year as president is to visit all of the chapters. So far, I have been fortunate to attend the joint meeting of the Pocono and Northeast chapters, where I was encouraged by the high attendance and interest in the society; and the Penn State Wilkes Bare Campus, where the chancellor was truly welcoming.

While at Penn State, I had the opportunity to speak to stu-dents; below are excerpts from that presentation. Prepar-ing the comments for the event refreshed my mind about things that are important to me as a surveyor. Whether the audience contains green or seasoned surveyors, instill-ing proper ethics and modeling correct techniques for those we are training and mentoring are important items to remember, so I share this with you:

In spring 1967, I started my surveying experience at Al-fred State College in New York. I remember sitting in my first class and having absolutely no idea of what surveying involved. After graduation in June 1969, I got my first job working for $3 per hour using a transit and 200-foot steel tape--no computers, plotters, fax machines or cell phones. We did not even have gammon reels for our plumb bobs. Though there is not enough time today to talk about my journey in surveying, suffice it to say I have seen an unbe-lievable change in technology.

One interesting point is that even though technology has changed, the essence of surveying has not—and neither have the important qualities that make a good surveyor. I would like to draw your attention to three equally impor-tant attributes that I believe are essential if you want to be a successful surveyor. They are not presented alphabeti-cally, but you will see at the end why I have chosen this order.

PersistentA surveyor needs to be persistent, which means deter-mined or continuous. Early in my career, I discovered the true meaning of this word.

One of first surveys I did in my company was a 6-acre parcel that had been created in the early ‘60s. According to the client, two surveyors had tried to survey the proper-ty but could not find any of the original monumentation.

My plan was to use the centerline of the road and a direc-tion of an abandoned railroad bed on the other side of the

road to calculate two alternatives for the property corners. I found an iron pipe buried 2 feet un-derneath an old wire fence. Using that corner I found another iron pipe buried 3.5 feet in a gravel driveway. I ended up finding all but one of the original corners. A surveyor has to be persistent; your shovel is one of the most important pieces of equipment you have.

At times, you will be tempted to give up too soon. Unfortunately, it is easy to take short cuts, get lazy when a project is going over budget, or the weather is affecting you, but a good surveyor will be persistent. You will develop a sense that will tell you that something just is not right.

ListenListen means to hear or pay attention; a surveyor needs to know how to listen—to clients, supervi-sors, and subordinates.

This goes beyond gathering facts and informa-tion: it has to do with the way we treat other people. I am sure most of us have heard of the Golden Rule, “Do unto others as you would have them do unto you.”

The point is if you listen to others and make sure you treat them the way you would like to be treat-ed you will never go wrong.

ScrupulousWhen I was considering the third quality I first thought of the word honest, and then I looked at the synonyms: conscientious, decent, ethical, fair, and honorable. It is interesting to me that the

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three surveyors whose images are carved into Mt. Rush-more were men known for their honesty and considered scrupulous men.

We have to be honest with our fellow surveyors, employ-ers, supervisors, coworkers, and clients, and scrupulous in all areas of our lives, whether in a personal or professional setting.

This also means that when we make a mistake we “step up to the plate” and make things right. On the very first job I did for an architect, I made a mistake on the location of the house. I had just purchased a new Robotic Instrument and made a mistake of some offsets. The architect called me and said that it looked like the location of the house was not correct. I checked my notes and found that she was correct. I called her right back, admitted that I was wrong, and fixed the plans and hand delivered them to her. She said that she was impressed that I did not try to cover up the mistake or make excuses. Rather than ruin-ing our relationship, it made it stronger.

You will make mistakes. The first thing I tell a person that is working for me is “If you make a mistake tell me im-mediately. Do not try to hide a mistake.” A prospective employer wants to have someone he or she can trust. If other professionals know that you are a scrupulous person and person of integrity that they can trust, they will want to work with you and recommend you.

These three qualities are the framework of all that we do as a surveyor. Do you remember them? To help you remem-ber I would like to use the acronym for PROFESSION-AL LAND SURVEYOR (PLS) to help you remember.

P=PERSISTENT: A surveyor has to be persistent. We cannot give up until we have exhausted all the resources available. We have to be tenacious in our pursuit of the resolution of a survey.

L=LISTEN: A surveyor needs to learn how to listen. And in listening remember the principle of treating others like he or she would like to be treated. Too many people fol-low the principle “Of do unto others as they do unto you,” or even worse “Do unto others before they do unto you.”

S=SCRUPULOUS: A surveyor must be a scrupulous person, a person of honesty and integrity. In a world that seems to have the philosophy of “buyer beware” or “watch your back,” we need to be men and women of honesty and integrity--we need to be scrupulous.

President’s Message Continued from Page 3

Richard L. Phillips, PLS, is a surveyor for ASH Associates in Kimberton, Pa.

Terri Ann Coleman

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have always given me strait answers to every question I’ve asked. Sometimes the answer is yes and sometimes the answer is no, but my clients get the truth from me and that’s what I get from Hayes.

There will always be logistical issues in surveying. The one thing I haven’t learned to do is to be in two places at once, but I am working very hard on learning how to do that. Hayes in Tennessee and me in Florida has never been an issue. The truth of the matter is that with overnight deliveries, the internet, email, FTP access and the telephone we can all do business with just about anyone we want.

I’m a Consulting Surveyor and I wouldn’t have it any other way. Things change and my business will change right along with them. The keys are motivation, support and always remembering that the harder we work, the more luck we have.”

Daniel galbraith, Psm, Plsgulf surveyors grouP, inc.www.gulfsurveyors.com

Dan specializes in surveying, GPS and robotics training, 3D modeling and data prep for machine control.

“What attracted me to Hayes at first was the ‘Worry-Free’ Lease because it fit so well into my business plan. It allowed me to get the equipment that I needed to start my business, without expending my entire budget. One of the most important parts of any business plan is the exit strategy. The ‘Worry-Free’ Lease allowed me to return the equipment with no further obligation if need be. As I grew, I learned the most important part of the lease is that I could trade up to better technology, without the obligation of making payments on equipment that I wasn’t using.

Advancing technology is at the heart of my business plan. It allows me to compete directly on projects in ways that weren’t possible 8 or 10 years ago. It takes a lot of effort to stay on the leading edge and it takes support as well. Hands down, Hayes has the best technical support that I have ever used. They know their equipment and they know their software.

When I need an answer, I need it now. I’m not real interested in excuses, and I don’t appreciate the line: ‘Johnny is busy right now and maybe he can call you back tomorrow.’ If I tell my clients that maybe I can meet their schedule, I’m reasonably certain they will tell me that maybe they can get someone else. Hayes understands that and they

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Conference Highlights

Left from back: David H. Artman, PLS, Vice President; Thomas J. Morganelli, PLS, Secretary; Byron W. Rimmer, PLS, Treasurer; and Robert R. Miller, PLS, NSPS Governor. Left from front: William L. Lehman, PLS, President-Elect; Rich-ard L. Phillips, PLS, President; and Emil A. Bove, PLS, Past President.

Distinguished Service Awards

Left from back: Keith Houser; John Huck, PLS; and William Oe-hler, PE, PLS. Left from front: David H. Artman, PLS; Amy Hopkins, SIT; and William Schoenagel, PLS. Not shown: William Beitler, PLS; Gregory Gress; Glen Larson, PLS; Kevin Karsnak, PLS; Ruth Ayn Sitler, EIT, SIT; Cynthia Skoriak; G. Windsor Tracy Jr., PLS; and Charles Zelenak Jr., PLS.

Scholarship Recipients

Left from back: Chris Jackson, Randy Lucas, Martin Smith, and Josh Witmer. Left from front: Luke Geiger, Scott Fusco, Tony Schulde, and Jason Marquiss. Not shown: Matthew Molinaro, and Matthew Osborn.

John G. Fuehrer II, PE, PLS Chair, Education Committee

President’s Award

Outgoing President Emil Bove, PLS, gives the 2008 President’s Award to Shari Taylor (center) and Laurie Troutman.

2009 Officers

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Conference Highlights

Plat Competition Letter from Patrick Lee (aka, Thomas Jefferson)

BLACKLINEorBLUELINE

Retracement Survey Category: 1st Place, David Alexander; Pickering, Corts & Summerson

ALTA/ACSM Survey Category: 1st Place, Robert Blue Jr., Robert E. Blue Consulting Engineers

Subdivision Plat Category: 1st Place, John Hopkins; All County and Associates, Inc.

Topographic Survey Category: 1st Place, David Alexander; Pickering, Corts & Summerson

Specialty Presentation Category: 1st Place, J. Michael Brill; J. Michael Brill & Associates, Inc.

COLOR

ALTA/ACSM Survey Category: 1st Place, Paul Homan; Gan-nett Fliming, Inc.

Topographic Survey Category: 1st Place, J. Michael Brill; J. Michael Brill & Associates, Inc.

Specialty Presentation Category: 1st Place, J. Michael Brill; J. Michael Brill & Associates, Inc.

January 29, 2009 To my friends at the Pennsylvania Society of Land Surveyors:

I’ve always said that it’s an honor to be invited to speak to a group, but it’s a delight to be invited back. To return for the third time is s special treat.

On behalf of all four of us, thank you so much!

Patrick Lee aka, Captain William Clark aka, Daniel Boone aka, Thomas Jefferson

Bookstore

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Ramblings by Chuck

Charles D. Ghilani, PhD

Establishing a Single Zone Coordinate System in Pennsylvania

IntroductionCurrently, Pennsylvania uses a dual-zone state plane coordinate system. As you can see from the Figure 1 there is a north and south zone that have a large overlap region in the middle of the state. These zones are based on the Lambert Conformal Conic map projection that uses a cone projection as it developable surfaces. The Lambert Conformal Conic was chosen on the fact that it holds a uni-form scale in an east to west direction. However, its scale does change in the north-south direction. It was this change in scale that led to the development of a dual-zone system. With the dual-zone system a relative precision of 1:10,000 could still be main-tained with the equipment in use at the time of its development in the 1930s. This meant that a survey performed in the 1930s did not need to reduce dis-tances to maintain its precision.

However, the equipment used in surveying practice today has advanced considerably. Today’s instruments are able to yield a precision of 1:40,000 or more easily. Furthermore, the eleva-tion factor can lead to preci-sions that are less than 1:10,000 and ALTA–ACSM standards require surveys with precisions

that are better than 1:20,000. Thus any survey using state plane coordinates needs to reduce all measured horizontal distances to the mapping surface. This involves both the scale factor for the line and an elevation factor. Addition-ally, if Pennsylvania is to ever attempt a statewide GIS, a single coordinate basis for the entire state is necessary. Thus Pennsylvania should convert its state plane coordinate sys-tem from a dual-zone to a single-zone. In the design of a single-zone system, the goal was to have a majority of the state continue with its 1:10,000 precision. Only small por-tions of the state in Erie County and along the southern border should be below 1:10,000 precision of today’s state plane coordinate system. A plot of the proposed single-zone coordinate system is shown in Figure 2.

by Bob Nargoski

As was mentioned in my previous article, each year sec-ond-year students are asked to develop a single-zone map projection coordinate system for Pennsylvania. Below is a typical paper produced after a semester of studying map projections, state plane coordinate systems, and reduction of observations when using state plane coordinates. This paper was written by Bob when he was a second-year student. Bob is currently in his senior year at Penn State.

Figure 1: Pennsylvania map depicting north zone standard parallels in green (short dotted lines) and south zone stan-dard parallels in blue (long dotted lines).

Figure 2: Proposed single-zone projection showing standard parallels and central meridian.

Map Projection and EllipsoidThere are several possible map projections that could be used for the single zone. However, the current Lambert Confor-mal Conic map projection has the advantage that it is con-formal and has uniform scales in the east–west direction. This means that the arc-to-chord correction does not need to be applied to angles or directions unless there are long sight lines. Thus the single-zone coordinate system will con-

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Applying this to the limits the two standard parallels yields standard parallels of: North:42°01’−0°23’=41°38’N South:39°43’+0°23’=40°06’NThe proposed single-zone system moves the origin to the southern design limit of 39°43’ N, but leaves the longitude of the central meridian (λCM)at 77°45’ W. To ensure that no location in the current state plane coordinate system has similar coordinate values to one in the proposed system and to ensure that there is enough overlap with our neighbors to the south to prevent negative coordinates, the false north-ing was changed to 400,000 m. The false easting remains at 600,000 m.

After the first attempt, it was noted that the precision in the center of the state was over 1:11,000. Thus the northern standard parallel was moved upward by 3’and the southern standard parallel was moved south by 1’yielding the design final values of: Northernstandardparallel:41°41’N Southernstandardparallel:40°05’N

tinue to use the Lambert Conformal Conic as its map pro-jection. This projection fits well in states like Pennsylvania that are long in the East–West direction. Since the National Geodetic Survey has adopted the Geodetic Reference Sys-tem of 1980 (GRS 80) for its reference ellipsoid, this design will continue to use the GRS 80 ellipsoid.

Design ParametersA majority of the area contained in the state is between 39°43’ N latitude and 42°01’ N latitude. Thus it was decided to design the system within these limits. However, it must be remembered that the actual map projection continues be-yond the design limits. The selection of these limits means that the northern portion of Erie County will have a scale factor that is below 1:10,000. Thus, the northern limit of the proposed single-zone system was set to 42° 01’ N. This ex-tended the design limits to about 24” above the east–west portion of the New York–Pennsylvania border. The southern limit was set to 39° 43’ N. This established a southern limit approximately 12” below the Mason-Dixon line, the south-ern border of Pennsylvania.

Two standard parallels are placed a distance that is about one-sixth of the total distance between the two design limits. One is placed below the northern limit and the other above the southern limit. These standard parallels are placed to minimize the area with precisions below 1:10,000 in Penn-sylvania. An example of this equation pertaining to the pro-posed single-zone system is

zonewidth 42 01 39 43 0 23'6 6

′ ′° − °= = °

Lat R (m) Tab Diff

K Prec

39°43' 7,506,622.958 30.84475 1.000108784 9,193

39°44’ 7,504,772.273 30.84466 1.000102967 9,712

39°45’ 7,502,921.593 30.84458 1.000097234 10,285

42°00’ 7,251,212.553 30.85695 1.000098368 10,16642°01’ 7,249,361.136 30.85722 1.000104186 9,59842°02’ 7,247,509.702 30.85749 1.000110090 9,08342°04’ 7,245,658.253 30.85777 1.000116080 8,61542°05’ 7,243,806.787 30.85805 1.000122156 8,18642°06’ 7,241,955.304 30.85833 1.000128319 7,79342°07’ 7,240,103.804 30.85861 1.000134567 7,43142°07’ 7,238,252.287 30.85890 1.000140901 7,09742°08’ 7,236,400.753 30.85919 1.000147321 6,78842°09’ 7,234,549.202 30.85948 1.000153827 6,50142°11’ 7,232,697.633 30.85978 1.000160419 6,23442°12’ 7,230,846.046 30.86007 1.000167098 5,98542°13’ 7,228,994.442 30.86037 1.000173862 5,75242°14’ 7,227,142.819 30.86068 1.000180713 5,53442°15’ 7,225,291.179 30.86098 1.000187650 5,32942°16’ 7,223,439.520 30.86129 1.000194673 5,137

Table 1: Excerpt of computational table for single zone showing regions with lowest distance precision.

...............

This provides a precision of 1:10,000 for most of the state with only the region from our southern border to about 39°45’ above 1:9100 and the region above 42° going from 1:10,000 down to its lowest value of 1:5000. This design limited the difference between a geodetic distance and map distance (scale factor, k) to the smallest area possible. However, it must be remembered that even 1:10,000 is deficient with today’s instrumentation and that the elevation factor can cause a greater difference between these distances in many parts of the state. Excerpts from the computations are shown in Table 1.

Continued on Page 10

In the design of a single-zone

system, the goal was to have a majority of the state continue with

its 1:10,000 precision.

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Table 1 lists the radius R, tabular difference (Tab. Diff.), scale factor, and precision for every entry. The tabular difference column is the change in radius per second of latitude. The derived zone constants Rb and sinφ0 are 7,508,473.649 m and 0.6545425130 re-spectively. The precision was derived using the for-mula 1/ 1-k . As can be seen in Table 1, excluding the northern portion of Erie County, the lowest pre-cision is 1:9100 for a majority of the state.

Arc-to-Chord CorrectionConformality only insures similar directional values in a small region about a point thus preserving the shape of the object. As sight lines become long, cor-rections must be made to bring the arc of the sight line on the ellipsoid unto a flat surface. Our instruc-tions were to determine the length of the sight line that would result in a 1/2 sec. correction to the direc-tion of the line. The equation used to determine ∆λ for a 1/2” correction is

where the northernmost latitude of 42°16’ was used in the computations. The yields a maximum sight distance for lines having a 1/2” correction of RN(cosφ)Δλwhere RN is the ra-dius in the normal at the latitude φand Δλ is in radians. This means that at 42°16’ (the tip of Erie county), any angle involving of sight line over 8300 ft should be corrected if a 1/2” difference is consider too large for the precision of the survey. For the southern border (39°43’), a 1/2” differ-ence between the direction of an arc on the ellipsoid and its equivalent on the mapping plane occurs with a sight line of more than 10,000 ft.

SummaryAt the time of its development, a dual-zone system was quite suitable for the commonwealth of Pennsylvania. With the advances in surveying equipment technology and the shrink-ing of the modern world it has become outdated. Although the requirement for the arc-to-chord correction was reduced from its previous value of 8 km to 2.5 km, not many surveys in Pennsylvania will involve sight lines of these lengths. Ad-ditionally, the advantages of having a single zone for a com-mon coordinate system in Pennsylvania far outweigh this negative side effect. A single-zone with its simplicity of use is the more suitable choice for our time.

Ramblings Continued from Page 9

zonewidth 42 01 39 43 0 23'6 6

′ ′° − °= = °

How KeyNetGPS works

KeyNetGPS is a network of Trimble Survey grade GPS (NetRS and NetR5)receivers or a VRS (Virtual Reference System). The network provides fastand accurate GPS positioning over wider areas than conventional RTKsystems. It is available at any time via wireless technology. There is noneed to set up a base station for local control, the network providescommon control or reliable State Plane Coordinates anywhere within thenetwork. In the field you have the extra assurance of the built-in integritymonitoring system that warns of any problems with data.

The use of networked reference stations, consisting of Trimble receivers,rather than a single base station allows for the modeling of systematicerrors. GPS observation data from our fixed reference stations is transmittedback to our central server in Allentown, PA. The Trimble RTKNet softwarethen performs quality and integrity checks, computes ephemeris andatmospheric errors, and models these errors for RTK surveying. The resultsare: reduction in errors, increase in accuracy, improved reliability andquicker RTK initialization time.

The benefit of using KeyNetGPS: Increased productivity

A user can arrive on any site in the network and within minutes be survey-ing at centimeter accuracy by themselves. High quality control is availablethroughout the network with a common coordinate base providingincreased productivity and high accuracy with less equipment. There’s noneed for a base station and radio. Using modern GPS receivers, and datacollectors with built in cell phone technology along with Bluetooth youcan work with a completely cable-free rover. And, you may be able to useyour current base as a second rover. KeyNetGPS will also work with modernTopcon and Leica RTK equipment.

Plans for growth of the KeyNetGPS network

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Conference Highlights

2008 Surveyor of the Year Award Presented to Robert R. Miller, PLS

Robert R. Miller, PLS, Oley, Pa., received the Penn-sylvania Society of Land Surveyors’ (PSLS) 2008 Surveyor of the Year Award during the annual PSLS conference in Hershey, Pa., January 25-28, 2009.

Miller is the director of surveying at Horizon Engi-neering Associates, LLC in Quakertown, Pa., which is in the Delaware Valley Chapter of PSLS. Active in chapter- and state-level activities for more than three decades, Miller has served in numerous lead-ership capacities, including state president, state di-rector, and chapter president. In addition, he served as as chairman of the PSLS Scholarship Commit-tee and subsequently an original trustee of the PSLS Scholarship Foundation, which benefits Pennsylva-nia surveying students.

“I want to thank you for presenting this prestigious award to me,” Miller said. “It means more than you know. One of the highlights of the conference has al-ways been the presentation of the Surveyor of the Year.

The most notable fig-ures in the history of our organi-zation are in this elite group of re-cipients. To be included in that circle is a hum-bling expe-rience.”

A surveyor for 38 years,

Miller is a longstanding member of the National Society of Professional Surveyors (NSPS), American Congress on Surveying and Mapping, Delaware Association of Survey-ors, and National Association of Home Builders. His roles at the national level presently include Pennsylvania governor of NSPS, serving the surveyors of the commonwealth in Wash-ington, D.C.; trustee of NSPS Foundation; and Pennsylva-nia scholarship chairman of Trig-Star, a national high school math competition sponsored by NSPS.

One of the highlights of Miller’s career was serving as chief surveyor for a project lead by producers of the television show Extreme Makeover: Home Edition, which visited northeast Philadelphia in 2005 to build a home for a family in need.

“All the work and u n u s u a l hours spent by the sur-veyors in-volved paid dividends as they saw the smiles and tears on the faces of the family that received the new house,” Miller said.

Active in his community, Miller has served as a member of his local school board, and presently serves as a Eucharistic minister for St. Catherine of Sienna Church. Over the years, he has volunteered his time as a hockey, soccer, and baseball coach, and drummer for the Reading Buccaneers Drum and Bugle Corps. Currently, he is president of the Reading Buc-caneers Alumni Association. Putting his surveying skills to work in the volunteer sector, he has helped build homes for local families through Habitat for Humanity, and surveyed land for the creation of several church and youth organiza-tion athletic fields.

PSLS extends congratulations to Miller, who has been a dedicated member of the society since 1976.

Member: 33 YearsChaper: Delaware ValleyHome: Oley, Pa.Employer: Horizon Engineering Associates, LLC

Quakertown, Pa.

The most notable figures in the history of our organization are in this elite group of recipients. To be included in that circle is a

humbling experience.”

Bob Miller receives Surveyor of the Year plaque from outgoing president, Emil Bove.

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Conference Highlights

You’ve cooked a hot meal that goes cold before it is eaten!

Your family’s primary vehicle is a Suburban!

Family outings always include looking for survey markers!

You’ve held the “zero end” of a measuring tape in public!

You have received field boots as a Christ-mas gift!

You’ve paid a credit card bill for surveying equipment-when you need a new washer and dryer!

You know what business your spouse is in, but have no idea what he/she does!

Your spouse can use complicated equipment and comput-ers, but gets lost just driving around!

You’ve driven through a snowstorm or a hot desert to get to a meeting you care nothing about!

You have spent all day learning arts & crafts that you will never use again!

Your spouse’s friends are more eccentric than he/she is!

You’ve waited all afternoon in a hotel lobby (after check-out) for his/her meeting to end!

You have sat through endless awards ceremonies and bor-ing after-dinner speeches!

If the luggage with the pin flagging tape coming around the baggage car-ousel at the airport, be-longs to you!

You Might be Married to a Surveyor If...

Your spouse is the most caring person you know!

Your spouse cares more about getting it right and not being perceived to have cheated anyone than about how much money he/she makes!

Your spouse respects his/her peers, even when he/she thinks they are wrong!

Your spouse cares about what happens to his/her profession, even after he/she is gone!

Your spouse feels a responsibility for the lives of his/her employees!

Yes, if you are married to someone with integrity, you are likely married to a surveyor!

If you didn’t relate to a couple of those things, you should relate to being married to a surveyor if:

Presenter : Walter G. Robillard, Esq., PLS

Featured Workshop: Boundary Conflict – Case Studies

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Our Surveying Students

Conference Observationsby Randall Myers, MS, PLS

Surveyors and those who write about the industry of-ten use the annual PSLS conference as the equiva-lent “half time” at a sporting event. It is a time to pause and ponder about the first half of the year, and see what competitors are purchasing and doing (since many survey and survey supply companies use this event as a launch pad for new products).

The products and technology unveiled this year marked a healthy evolution for the industry, especially comparing it to 10 years ago. Even spending three days there, one regret for this surveyor was not being able to see more booths and talk to more exhibitors. My observation was that all booths had something interesting and beneficial to offer.

As with most surveying ex-hibits, field equipment s u p p l i e r s loomed among

the largest and boldest on the floor. Major suppliers in-cluding Topcorn, Trimble, and Leica were present. In other booths, a healthy cross section of the industry displayed in-surance brokers, PSLS exhibits and bookstore, and contract-ing services.

Amidst the activity, one thing I noticed was that the “white-haired” influence was there in force; it is apparent that the average age in this industry is rising, and many people I spoke with shared a concern for new blood with fresh ideas. Perhaps it is time to return to co-op programs to cultivate new talent. We should all applaud and support efforts of true “champions,” like Dr. Charles Ghilani who tirelessly promotes the industry to students at Penn State University, who seek new talent. Like-minded individuals, such as Dr. Ghilani’s colleagues Tom Seybert and Wes Parks, are also driving the search for the next generation of surveyors. Cer-tainly, after I witnessed the “graying” of the industry across the exhibit floor, their efforts, and the efforts of people like them, are greatly needed and appreciated.

“The products and technology unveiled this year marked a

healthy evolution for the indus-try, especially comparing it to

10 years ago.”

We consider ourselves to be that honest, true, and selfless

group of professionals who live by our own code of honor...

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Feature Article

Recently, a fellow surveyor asked me the following question “Why does no one ever ask who surveyed that new building, bridge, park, road, etc.”

True enough, the public is often (if not typically) aware of the architect who designed a structure, or park, and the engineer who designed a bridge, scenic highway, or site plan. They are even likely to know the contractor who built it.

Meanwhile, the surveyor who provided the data for other professionals to design, and the contractor to build, remains anonymous!

Throughout history, the surveyor (with a few notable exceptions) has been in the background of the devel-opment of our country. All the while, being a vital component of the backbone of society. Why is this the case?

Certainly, we surveyors don’t have to tell each oth-er of the importance of the work of our predeces-sors, and indeed of ourselves. We are proud of our heritage. We worship at the altar of Mt. Rushmore where our surveying heroes Washington, Jefferson, and Lincoln are immortalized (along with that “oth-er guy”).

Surveyors: Unsung Heroes or Out of Touch?The following is an article condensed from a keynote address by Curtis W. Sumner, PLS, executive direc-tor, American Congress of Surveying and Mapping (ACSM)/National Society of Professional Surveyors (NSPS).

In fact, we revel in the self-shared glory of considering our-selves to be the “Last of the Rugged Individualists.” We con-sider ourselves to be that honest, true, and selfless group of professionals who live by our own code of honor that can re-sult in financial hardship to ourselves while we are in service to our fellow citizens.

In our interaction with other professionals, we are often ex-pected to correct their work (or at least bring errors to light), and to hold the hand of the contractor to avoid costly mis-takes, or catastrophe.

Surveyors have traditionally been the buffer between an ap-provable (but not buildable) plan, and one that can be con-structed. In my 40 plus years of surveying, I don’t recall ever being presented with a plan from an architect in which all of the incremental dimensions added up to equal the overall total dimension shown.

Likewise, rarely have I seen a design plan from an engineer that doesn’t require some level of recalculation. It almost seems as though the better technology becomes, the more plans tend to be “cartoons” that look good, but are often not mathematically or geometrically sound.

In spite of the importance of the services surveyors provide to fellow professionals, and to the public at large, we are of-ten held in low esteem by our fellow professionals and others with whom we must work, even those for whom we toil in apparent selflessness.

Why do we not get the respect that we think we deserve? There are several schools of thought with regard to this ques-tion.

Some say that it is due to the low requirement for the formal education necessary as a prerequisite by more than half of the 50 states to qualify for taking the examinations to attain licensure as a surveyor. Some even question the professional-ism of surveyors due to a lack of formal education. While I understand that the title “professional” may be defined to be applicable only to those who have attained some prescribed academic degree requirement, I do not believe that formal education and professionalism are synonymous. Profession-alism, as it is typically understood to be defined relative to the services one provides, is a personal achievement that is based on character and the manner in which individuals con-duct themselves in the pursuit of their work. It is not based on the number or hierarchy of degrees one holds. There are many instances in which this is evident in society.

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Still, the concept of aligning the title of professional with formal education is becoming more and more prevalent, and should not be discounted. It is certainly true that exposure to the broad opportunities in surveying practice is much more available to students in surveying-related college and univer-sity programs than it is to an individual who merely gains ex-perience while working for a licensed surveyor whose servic-es are limited to only one, or a few, of those areas of practice.

Others say it is because we bid our services against our com-petition to the ultimate lowest price. There is much evidence of this, also. Why would clients perceive that our services are worth more than we seem to believe them to be? When someone continues to lower the cost of services in order to “get the job,” clients will think one of two things: 1) this person must not think his/her services are worth much; or 2) this person must have been trying to cheat me with the first price quoted since it has now been low-ered.

Neither perception is a good one for the surveyor, and our profession in general. Even if one “bids” for work, it makes sense as professionals for us to understand the cost of doing business and the value to the client, and the public, of the services we provide.

Still others say it is because we don’t present ourselves to the public in the same manner as do other professionals. Many believe it is a result of our relative inability to articulate well what it is that we do, and that our work is much more than simple applications of mathematics. Additionally, it is per-ceived that we do not dress appropriately for the situation at hand. An uncle of mine once stated that people are supposed to judge you based on what is on the inside, not on your ap-pearance outside. One of his sisters remarked, “If they don’t like what they see on the outside, they may never bother to look at what is inside.”

How many times have we heard it said, “We are our own worst enemies”? There is some element of truth in all of these things regarding us as a whole. However, other profes-sionals suffer from negative perceptions also.

Doctors get sued more often that do we. Lawyers are reviled constantly. Engineers are sometimes considered by some to be Nerdy. Some consider ar-chitects to be aloof and illogical.

Contractors are sometimes put into the category with those who are considered unscrupulous. The list goes on and on!

So why are all of them more well-known, and in spite of the criticisms, much more prominent (and yes, respected) in the minds of the public, and young people who are planning for their futures?

What do they have that we don’t have? What do they do that we don’t do? How many times have we heard the radio commer-cials extolling the virtues of the architect? How much press is there for EWEEK and MATH-COUNTS?

While personal, local, and state efforts are critical for presenting ourselves as

professionals, and our profession as a viable career option, without a national effort similar to those of doctors, lawyers, architects, engineers, and even con-tractors, our chances of gaining the recognition and respect due to us remain seriously hampered.

Why are organizations such as the AMA (doctors), ABA (lawyers), AIA (architects), NSPE and ASCE (engineers), AGC (contractors), and even MAPPS (professional photogrammetric surveyors) more ef-fective than are our national organizations (ACSM and NSPS) in their efforts to influence legislation and policy, present the professions they represent as viable career options, and be well recognized by the general public.

I think a very important reason is because the prac-titioners they represent recognize that, while the registration laws governing their practice are state laws, and unity of effort at the state level is critically important, they will only have an impact on a na-tional scale by acting collectively.

Continued on Page 18

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The reason that these other organizations are so ef-fective isn’t because they care more, or that they have more talented and persistent flag bearers than do we.

It is because their constituents support their national efforts to a higher degree. A higher percentage of potential members support all of these organizations than do those of our national organization.I don’t want this to come across as a sermon chastis-ing those who are not members of ACSM/NSPS. While that would be a wonderful thing, in my opin-ion, the message here is that we must find a way to act together, not against each other.

It is a proven fact that what we seek will not just come our way. We have to work for it. We must temper our desire to think of ourselves as rugged individualists with the reality that only by banding to-gether will we be able to make a difference in our quest for more prominence and re-spect as a profession.

As we gather here to-night, Department of Labor Auditors in Maine are refusing to recognize surveyors (licensed or not) as professionals.

FEMA has decided to allow practitioners in Flood Determination companies to file Letters of Map Amendment using the online eLOMA option.

Surveyors are being cast by some as being irrelevant due to new technologies that allow almost anyone to gather geospatial data and integrate it into docu-ments that appear to the public to have the same (if not higher) reliability than those prepared by sur-veyors.

Surveyors are being asked to bid their services to other professionals, although those professionals were selected using Qualifications Based Selection (QBS) criteria, commonly known as the Brooks Act.

There is concern that our profession is dying because we cannot attract enough young people to sustain it. These are but a few of the challenges that we face.

What form the collective effort will take to accomplish our goals is less important than the fact that it must occur.

So, are we unsung heroes, or are we out of touch with the realities that surround us? I suppose it is a little bit of both.

Our contributions to the well-being of our fellow citizens are clearly under-recognized, if not unappreciated. On the other hand, we must understand that only through substan-

tial effort on our part will that recognition come.

These are tough economic times, and it is nat-ural for us to look inward toward the sustain-ability of our respective businesses. I wish that I had a simple solution that would restore the confidence necessary to overcome the situa-tion.

Unfortunately, it appears that finding that solution will be difficult. All of the tenets on which I have always depended for a successful surveying business are still valid, but without consumer confidence, obtaining work will still be difficult.

Still, I am confident that you share my con-cern for the present, and future, well-being of our profes-sion.

Now, at the beginning of my 11th year as the Executive Di-rector of ACSM/NSPS, my resolve to address the challeng-es we face remains undeterred.

I trust that you will, if not immediately, then as times get better, join me in banding together through a stronger and more sustainable national presence that is not only desir-able, but essential.

Some of you have heard me speak before, and therefore, you know that I often end presentations using advice from my Mom years ago when I asked her what I could say to a large audience that would leave the most positive impression.

She said, “Tell them you’re done, they’ll really like that.” So, I’m done.

Unsung Heroes Continued from Page 17

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areour

I attended the 25th anniversary of the South Dakota Soci-ety of Professional Land Surveyors in September near Rap-id City, S.D. Eighty-two surveyors from across the United States attended. This conference took precedence over my annual motorcycle ride to Sturgis, S.D.

While there, I had the opportunity to catch up with some friends: David Ingram, Virginia; Curt Sumner, ACSM; past presidents of the South Dakota chapter; and fellow survey-ors. The weather was perfect and allowed us to spy buffalo, mule deer, and antelope while driving through the mountain.

As the photo shows, we gathered at the base of Mt. Rush-more for a ceremony to commemorate the South Dakota’s society and the “three surveyors and the other guy.” It was a pleasure to learn about this chapter’s involvement in the surveying community. For starters, the members have been instrumental in planning financial assistance to college stu-dents who major in surveying; they have done so since 1991. In addition, they have awarded approximately 85 scholar-ships to date, and they have also had more than 45 high

Remembering Rushmoreby Randall Myers, PLS

school students involved in the national Trig-Star program.

I extend many thanks to Warren Fisk, 2007 South Dakota chapter president, and his staff for making us feel at home during this exciting event.

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Chapter News

Lehigh-Valley Your president is on the ball! Rick Phillips has already

begun meeting with chapter officers to hear their concerns. In this picture are Lehigh Valley Chap-ter officers, from left to right, Bruce Gustin, PLS, vice president; Rick Phillips, PLS, state president; Nick Remy, PE, PLS chapter president, (seated); Tom Morganelli, PLS, state secretary; and Al Bradbury, PLS, fellow. Absent from the photo was Bill Beitler, PLS, state director. The group met on Wednesday, February 25, 2009, at the Pottstown Diner, Pottstown, Pa. by Thomas J. Morganelli, PLS, State Secretary

Delaware-Valley Relay for Life Fundraiser with Ameri-

can Cancer Society. Join the team and raise mon-ey or walk for one hour on May 8 between 6 p.m. and May 9 until 11 a.m. (yes that includes the mid-dle of the night); buy a custom 40 year anniversary PSLS T-shirt, sweatshirt, or long sleeve T-shirt; or give cash! To participate, visit www.main.acsevents.org/goto/pslsrelay.

South-Central has enjoyed an eventful fall/winter season, beginning with the elec-

tion of new officers in October for the 2009-2011 term. The chapter is proud to present these officers:

David Anderson (President) Ron Garis (Vice President) Brad Foltz (Treasurer, Director) Tom Farcht (Director) Ruth Ayn Sitler (Secretary) Nicole Tocco (Chapter Director)

Elections were followed with a presentation by Dr. Walter Powell, executive director of the Conococheague Institute. Dr. Powell presented “The Building of the Forbes Road in 1758” to mark the 250th anniversary of the Forbes Cam-paign. His presentation provided an entertaining and edu-cational insight into the unique challenges faced by the sur-veyors and engineers tasked with building the Forbes Road.

After a brief holiday break, chapter mem-bers and their fami-lies gathered for a few frames of fun at the 4th Annual South Central PSLS Bowling Event at Suburban Bowlerama in York, Pa., on January 18.

Upcoming chapter events include a meeting on April 29 at 6:30 p.m. at the Black Horse Tavern in Shippensburg. Nor East Mapping, Inc. will sponsor this meeting and speak about photogrammetric mapping services. RSVP to the South Central Chapter Secretary Ruth Ayn Sitler by April 21 to attend.

Other meetings include a PennDOT Right-of-Way presen-tation in May, and an evening with PSLS President Rick Phillips, PLS (date TBD). Visit http://rsitler.home.comcast.net/~rsitler/index.htm for more chapter details.

Finally, the South Central Chapter extends congratulations to the following members on their achievements:

Nicole Tocco, earning her SIT license Gregory Sorce, earning his PLS license

by Ruth Ayn Sitler, EIT, SIT, Secretary

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Feature Article

Estimating Stormwater Detention Volumes for Land Development Planningby Thomas A. Seybert, PhD, PE

Government regulations (municipal, county, or state) often require stormwater design for land develop-ment to handle multiple runoff events. For exam-ple, the municipality of Dallas Township, Luzerne County, Pennsylvania, requires all land development projects to handle the 2-yr, 10-yr, 25-yr, and 100-yr runoff events. Some government regulations re-quire more some less, but most require three or more controlled events. A hydrologic analysis of each de-sign event must be completed and the process can be lengthy. A thorough stormwater design requires the use of involved hydrologic computations for both the existing and future conditions including:

• quantifying land use,• estimating runoff coefficients,• computing concentration times, and• building design hydrographs for each

controlled event.

Using the results of this hydrologic analysis, the designer must then estimate detention basin size (storage required), and route the design flood hydro-graphs for all controlled events through the basin to check the effectiveness of the detention facility. This entire process is computationally intensive but nec-essary for a complete and accurate hydrologic design of a stormwater management system.

This intensive process is not needed, however, to make a preliminary estimate of detention facility size required for a particular land development site. De-tention basin size is controlled only by the manage-ment of the largest post-development runoff event. Therefore, a simplified analysis of a single event will give a reasonable estimate of what the land devel-oper should expect in terms of lost land area to meet stormwater management needs. This number is of great value to a land surveyor or land developer who is involved in evaluating the viability of a parcel of land for development.

Runoff Difference Method

A quick and reasonably accurate procedure for estimating the required storage volume for stormwater detention can be performed based upon the assumption that storage required for stormwater detention is equal to the post-development runoff volume minus the pre-development runoff volume. This difference represents the increase in total runoff due to development, so this is a logical assumption and it is easy to determine. The method is document by McCuen (2004) and (Seybert, 2006) and relies upon the relation

(1)

where Vs is the required storage volume in acre-inches, A is the site drainage area in acres, Qpost is the runoff depth for the developed condition in inches, and Qpre is the run-off depth for the pre-development condition in inches. The method has been observed to give consistently conservative estimates. Therefore, if the project is viable using the results of this simplified method, there will not be any surprises when the final design is completed using the more accurate, and time consuming methods.

The estimate of runoff depth (inches) is computed using the National Resource Conservation Service (NRCS) curve number (CN) method. The CN value is a function of land use, soil type (hydrologic), and land use condition. Values of CN are provided by the NRCS in the document Urban Hydrology for Small Watersheds, TR-55 (USDA NRCS, 1986), with more complete data provided in other sources (USDA NRCS, 2002).

Runoff depth Q is computed using the NRCS runoff depth equation

(2)

where Q is direct runoff in inches, P is precipitation in inch-es, and CN is curve number. The proposed site is assigned curve number values based upon land use and the hydro-logic classification of the site soils. This is done for the pre-development and post-development conditions. Since most sites contain more than one land use and sometimes more than one soil type, an average value of CN for the site is de-termined using area-based weighting. The average CN value is equal to the sum of the products of all CN values and their

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associated areas, divided by the total drainage area. In equa-tion form

(3)

where CNavg is the area-based weighted CN, CNi is the curve number of an individual land use classification, Ai is the area of an individual land use classification, and n is the number of land use classifications in the drainage area.

As a matter of interest, curve num-ber weight-ing is appro-priate only when the CN values within a drainage area do not vary dramatically. Some academics suggest that CN values should be within a range of 5 points, but practicing engineers often use a CN range as wide as 10 to 20 points while still obtaining reason-able results. A wider range becomes inaccurate for smaller precipitation amounts of approximately 3 inches or less.

Once the average CN value is determined, the analysis turns to design rainfall. The design rainfall depth P for the largest design event must be determined. Although the CN meth-od does not require a specific rainfall duration associated with P, many regulatory agencies require the use of a 24-hr storm. Rainfall information may be provided by a regulat-ing government agency, however finding the design rainfall depth is often left up to the design professional. A good source for rainfall data for the United States is the Hydro-meteorologic Design Studies Center (HDSC) on the Na-tional Oceanographic and Atmospheric Administration’s (NOAA) web site (http://www.nws.noaa.gov/ohd/hdsc). The data quality at this site varies by state and the designer should evaluate data quality before using the information. However, any state that has data provided from NOAA’s Atlas 14 (NWS, 2004) is guaranteed to have good quality data. Similar high quality data can be found in PennDOT’s Publication 584 (PennDOT, 2008).

With CN values for pre-development and post-develop-ment determined, and a known rainfall depth P, the runoff volumes for both conditions Qpre and Qpost are computed using Equation 2, and the estimated storage volume for de-tention is computed using Equation 1. The process is illus-trated by example.

Storage Estimation Example

Consider a parcel of land located in Harris Town-ship, Centre County, Pennsylvania which contains 61.7 acres of meadow and woods, both in good condition and protected from grazing. It is to be developed into the Pine Hills Subdivision with pre-development topography and land use shown in Figure 1. The development is proposed to contain ½ acre, single family lots. The local subdivision and

land development ordinance requires at least 20% of the property to be reserved for a community park. An existing resi-dential subdivision adjacent to the site on the eastern boundary uses a stormwater diversion swale to control surface runoff upstream of the Pine Hills site. Route 45 to the south provides a man-made runoff

break-line and the north, east, and west boundaries run perpendicular to contour lines at all locations. This unique situation makes the property bound-ary essentially identical to the drainage area bound-ary. The proposed location of a detention facility to manage stormwater runoff is just above point O in the existing natural swale. The maximum design rainfall depth is the 100-yr, 24-hr rainfall which is 6.1 inches.

To estimate the volume of the detention facil-ity, curve numbers are assigned to the existing and proposed land use conditions. The first step in as-signing CN values is to determine the hydrologic soil groups (HSGs) present on the site. For this parcel, the soil survey for Centre County, Pennsyl-vania (USDA SCS, 1981) is used to map soils by name. Then, the HSG cross-reference list provided in Appendix B of TR-55 (USDA NRCS, 1986) is used to assign soil types A, B, C, or D. Results are overlaid on the land use map shown in Figure 2. Each combination of land use and soil type repre-sents a different soil-cover complex and CN value. For the pre-development condition, these areas are measured and shown in Figure 2. CN values are assigned to each complex based upon information provided in Table 1, which is a subset of the data provided in TR-55 (USDA NRCS, 1986). Results are shown in Table 2.

CN Averaging is used in this example since the variation range of CN values is 16 and the design

Rainfall information may be provided by a regulating government agency, however finding the design rainfall depth is often

left up to the design professional.

Newsletter Changes

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PA Surveyor to Go Paperless!

Name

Preferred Mailing Address

Home Phone w/ area code

Business Phone w/ area code

Fax E-mail

q Yes, I need to receive ThePennsylvaniaSurveyorby mail. My information is below.

Form for Paper Version ofThePennsylvaniaSurveyor

clip to mail

Speakers

Tom Phillips, PLS

Bernard Telatovich, PE, Esq.

David Logue, PLS

Justin Klein

With today’s economy in constant flux, many busi-nesses are watching their budgets closely--Penn-sylvania Society of Land Surveyors is following suit.

As a professional society, we want to ensure that we spend funds wisely while maintaining quality ben-efits for members. To save on paper, printing, and mailing costs, The Pennsylvania Surveyor will now appear quarterly via a link on the PSLS Web site.

If you don’t have Internet access, the society will provide paper copies to you upon request.

As always, we welcome articles and photos for sub-mission, and we will continue to provide you with news that is relevant to the surveying field.

Thank you for bearing with us during this transi-tion. If you need to receive your edition via tradi-tional mail, please fill out the form on this page and fax (717-540-6815) or mail it to:

The Pennsylvania Surveyor Pennsylvania Society of Land Surveyors 2040 Linglestown Road, Suite 200 Harrisburg, PA 17110

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This process is repeated for the post-development condi-tions. Figure 3 shows the proposed site development which includes placing a community park of 14 acres (22% of the parcel area) in the south-eastern corner of the property and clear-cutting the small patch of woods to make room for the layout of ½ acre lots for residential housing. CN data is gathered for the site using Table 3 and an average CN value is computed. Results for the post-development give an aver-age CN of 77.

With average CN values for the pre-development and post-development conditions, runoff depths for the 100-yr event are computed using equation 2.

Equation 1 is used to compute an estimate of required stor-age for the detention basin.

This simple method estimates the storage volume to be about 195,000 ft3. Some rough calculations can be used to estimate surface area required to build a pond of this size. For this example the following geometry of the basin is as-sumed:

• Rectangular basin on a relatively flat site (0 to 2% slopes)• Side slopes of 5H to 1V• A 5-ft maximum water depth• Two feet of free-board• A 10-ft wide embankment• A 15-ft buffer around the basin

With this criteria, calculations estimate that the pond will require about 84,200 ft2 of surface area, or about 1.9 acres. This area is equivalent to about four ½ acre lots. The developer now has a very good estimate of the number of lots that are likely to be available (or lost). This information can be used in the planning process to determine if the project is economically feasible.

Actual Storage Required

A rigorous evaluation of storage requirements for this example site, using hydrographs and detention basin routing methods, shows that the actual stor-age required to manage the 100-yr runoff event is 166,000 ft3. Therefore, the runoff difference meth-od gave a conservative estimate of storage required, overestimating by about 17 percent. Thus the runoff difference method is more than adequate for plan-ning purposes and provides a small factor of safety in the planning process.

Conclusion

The runoff difference method for estimating stor-age required for stormwater detention in a typi-cal land development scenario is simple compared to the more rigorous calculations encountered in a complete stormwater management study. Several involved calculations are not required including cal-culations for time of concentration, creation of pre-development and post-development hydrographs, sizing of a detention pond outlet structure, and routing hydrographs through a detention basin. All of these calculations are time consuming and can be eliminated in this preliminary method. It has been observed that the runoff difference method of es-timating storage requirements is conservative, thus ensuring that any planning decisions based upon the preliminary results will always err on the safe side of feasibility.

rainfall depth is 6.1 inches. The calculation is summarized in Table 2. CN values should always be rounded to the nearest point, so the CN value for the pre-development site is

Thomas A. Seybert, PhD, PE, is an associate professor of en-gineering at Penn State Wilkes-Barre, where he teaches sur-veying fundamentals in the Surveying Technology and Sur-veying Engineering programs. He also teaches engineering courses in drainage design and stormwater management. He is the author of the book “Stormwater Management for Land Development” (Wiley Publishers) and one of the authors of the Virginia Tech/Penn State Urban Hydrology Model (VT/PSUHM).

PSLS Membership Application

Name Address City, State, ZIPIf Student, College/UniversityBusiness or School Address Home Phone w/ area code Business Phone w/ area code Fax E-mail

Preferred Mailing Address: q Home q Business Professional Registration If Applicable:State Number State Number

Please list any other professional/technical society membership:

Please indicate the membership grade for which you qualify:q Member………………………………….$165.00 per year (Surveyor licensed in Pennsylvania.)q Associate …………………………………$95.00 per year (Not presently licensed.)q Corresponding…………………………… $85.00 per year (Member of another state society where you reside.)q Sustaining………………………………..$300.00 per year (Firms having an interest in land surveying)q Student…………………………………….$15.00 per year (Enrolled in a Pennsylvania College or University.)

Chapter Affiliation Requested: (Not applicable for Corresponding or Sustaining Membership) Please list names of two PSLS members, if you know any, who are acquainted with your qualifications and will sponsor your application:

Primary Sponsor Sponsor

I hereby apply for membership in the Pennsylvania Society of Land Surveyors and, in doing so, agree that I will actively support the Bylaws, aims, and objectives of the organization. Signature of Applicant Date

Pennsylvania Society of Land Surveyors2040 Linglestown Road, Suite 200Harrisburg, PA 17110P: 717.540.6811 F: 717.540.6815www.psls.org

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Pennsylvania Society of Land Surveyors2040 Linglestown Road, Ste. 200Harrisburg, PA 17110

PRSRT STDU.S. Postage

PAIDHarrisburg, PA

Permit No. 1144

www.psls.orgwww.psls.org

UPS discounts to members of the Pennsylvania Society of Land Surveyors include:

• $1.50 off NDA letters • 10% off NDA packs • 20% off World Wide Express • 10% off 2nd Day Air AM Letter • 10% off 2nd Day Air AM Pack Members can sign up for the program by calling 1.800.325.7000.

Discounts for PSLS Members!

Conference Highlights

The PA Surveyor is Going Paperless!

See Page 24 for details.