44 Years of Advancement in Groundwater Studies

Robert G. Gerber, P.E. & C.G. Ransom Consulting, Inc.

Robert.Gerber@RansomEnv.com March 2015 Maine Water Conference

Thales of Miletus: first scientist

• 6th century BC

• “water is the first principle of nature”

• First to theorize that nature can be explained in rational terms and that nature can be modeled (a summary of my career: modeling geologic and hydrologic systems)

• It is the achievable task of science to discover a conceptual model that corresponds to nature and accounts for observed phenomena

For the young people in the audience, I hope this presentation answers the

question: What did you do to succeed as a professional?

• Good education; hard work; long hours • Continual learning • Staying open to and pursuing fields of study that interested

me (which helped me to bring passion to my work and gradually change what I did over time to keep life interesting)

• Being willing to take on large responsibilities and challenges, maybe even before I was fully ready

• Developing new lines of business by doing the first couple of projects at well below market value

Education

• MIT B.S. Civil Engr 1966-70 – Started computer programming as a freshman with

machine code, FORTRAN, ICES, others – Primary concentration geotech engineering; 3 geology

courses – 4 semesters calculus; 2 physics; 1 chemistry

• Stanford M.S. Civil Engr 1970-71 – More geotech; marine engr; some groundwater

• Reading groundwater & modeling textbooks • Mentoring by Fred Bendtsen, Peter Johnson, Henry

Bacon, and Jack Rand and learning from many others • Trying and failing and trying again

Employment Progression

• Summers 1967, 68, 69 surveying, concrete, soil, steel inspection at Maine Yankee during the nuclear plant construction

• Summer 1970, 1971-72 Consumers Water Co engr. on water supply & water utility design

• 1972-74 20% owner in env. consulting firm doing basic geology & engr.

• 1974-76 CMP managing geologic & env. studies for proposed Sears Is. Nuclear plant

• 1976-1998 president of RGGI doing groundwater & surface water modeling & geotech engr.

• 1998-2007 ran Stratex env. consulting company within law firm of Bernstein Shur

• 2007-2011 engr & geologist at Sebago Technics • 2011-present engr & geologist at Ransom Consulting

RGG skill set progression

Expert Witness Work

• First Superior Court Trial 1978, 7 years out of school • Expert in 4 states plus Delaware Fed. District Ct. • Testified 8 times in Maine Superior Courts, including

one time as Expert of the Court • 2 Maine Land Damage Board hearings, 3 mediations, 4

arbitrations • 8 times as a listed witness with case settled before trial • As State Dam Inspector presided over 3 dam safety

hearings and wrote opinions and orders on same • Testified in 15 Maine Board of Env. Protection hearings

and 3 LURC hearings; hired by BEP as assistant to the Board in the HoltraChem hearings

• Presented testimony in FERC and NRC proceedings

Most influential technical books • Leavitt & Perkins Glacial Geology of Maine (1935) • Ground Water and Wells (1966 & later) • Seepage, Drainage and Flownets (Cedergren, 1967) • Ground-Water Hydraulics (Lohman, 1972) • Groundwater Pollution (Fried, 1975) • Ground Water Handbook for the State of Maine (Caswell,

MGS) • Hydraulics of Groundwater (Bear, 1979) • Seepage & Groundwater Flow (Rushton & Redshaw, 1979) • User Manual for AQUIFEM (Townley & Wilson, 1980) • Analytical Methods in Ground Water Hydrology (Wilson, 1981,

BSCE lecture series) • Modeling Groundwater Flow & Pollution (Bear & Verruijt,

1987) • USGS groundwater model user manuals

Groundwater Model Progression

• USGS Konikow & Bredehoeft 1978 2-D FD Transport & Dispersion using MOC

• Townley & Wilson 1980 AQUIFEM 2-D flow FE model using Galerkin elements

• Pinder 1988 Princeton Transport Code (hybrid quadrilateral FE in horizontal; FD in vertical) flow & transport

• USGS 1988 McDonald & Harbaugh MODFLOW (3-D FD flow) • USGS Voss 1984 SUTRA (2-D FE flow & transport) • MT3D-DOD 1997 3D FD solute transport coupled with MODFLOW • Zheng & Wang 1999 MT3DMS FD solute transport coupled with

MODFLOW • Guo & Bennett 1998 SEAWAT FD flow and transport that is density

dependent

1970s Tools

• HP-67 programmable calculator

• IBM Selectric Typewriter

• Ink pens and letter guides

• Engineer’s scale

• Right triangles and protractor

• Dumb computer terminal/printer with 300 baud analog phone modem connection to Control Data Corp

1980s Tools

• TRS-80 computer with 3-bay aux. disk drive

• Copier that could shrink and enlarge

• Dataloggers for field measurements

• IBM PC

• Visicalc & word processing programs

• dBase II database program

• Surfer & Grapher

1990’s Tools • Microsoft Office software • Geostatistics software • Geoprobe drilling capability & field analytical testing,

including field GC • Laser printers • Rockworks (3-D modeling of geologic structure) • Chemstat for statistical analysis of water quality data • MathCAD • Ucode, pilot points and PEST (parameter estimation)

auto-calibration software for groundwater models with statistical analysis

• ArcGIS

2000’s Tools

• 3-D visualization software

• Big databases and geodatabases, including MEGIS, DEP, and MGS digital maps

• Widespread use of ArcGIS and orthophotos

• Google Earth

• LiDAR

• DEMs (Digital Elevation Models)

• Hand-held GPS for field location

Building a company from 1 to 25 employees

• Jack Rand was my mentor and he believed in working without employees so I emulated him for years after becoming a consultant in 1976

• Then Carol White came along and offered to work for me for free but since I couldn’t not pay her, she became my first employee

• By 1985 I had 10 people working out of my home in Harpswell. By 1995 we had 25 people in RGGI, of which 15 were stockholders. I only owned 45% of the stock when we sold to Jacques Whitford in 1995.

How did this happen?

• In the mid-1980’s Jack Rand and I landed a huge job with Georgia-Pacific. It was too large for us to do on our own so I had to start hiring and subcontracting. By the late 80’s we had three projects, each with total fees over $1,000,000 plus many other projects of all sizes

• To get to work on large complex projects you have to have a team with diverse talents

• The need to build a team led to my interest in management and team building in 1990-95 and RGGI probably did more of this in-house training than any other consulting firm in Maine (10% annual budget)

Major projects (out of 2000) • Sears Is fault investigation 1975-76 • Rowe nuclear plant slope stability studies 1978-1982 • Maine DEP & CDM McKin Chemical Superfund site groundwater

characterization & modeling 1982-84 • Georgia-Pacific Woodland 1985-87 leaking lagoon, landfill evaluations,

new landfill design • Wheelabrator-Frye Sunkhaze & Chemo bog hydrologic characterization

studies 1984-85 • Waste Mgmt 1989-97 Norridgewock Landfill groundwater characterization

& modeling • Maine Yankee decom. 1999-2005 soil & groundwater contam.

characterization • Conn. Yankee decom. 2004-2006 groundwater characterization &

modeling • Yankee Rowe decom. 2006-2011 groundwater characterization &

modeling • Seabrook nuclear plant 2011-present groundwater characterization &

modeling

Major groundwater papers

• Confined Aquifers in Glacial Deposits in Freeport, Maine, in Maine Geology: Bulletin No. 1, GSM, January 1979.

• Evaluation of Wellhead Protection Methods. Report to Maine DEP and Maine DHHS, 1988

• The Applicability of Porous Media Theory to Fractured Rock Flow in Maine (co-authored with K. Bither & O. Muff), in Proceedings of the Focus Conference on Eastern Regional Ground Water Issues, pp. 207-220, October 29-31, 1991, Portland, Maine

• Ground Water Recharge Rates for Maine Soils and Bedrock (co-authored with Charles Hebson), in Maine Geology, Bul. No. 4, The Geological Society of Maine, 1997, c/o The Maine Geol. Survey, Dept. of Conservation, State House Sta. 22, Augusta, ME 04336

The GW Learning Progression

1) Finding groundwater supplies in sand and gravel 2) What does the term “safe yield” mean? 3) Finding high-yield zones in bedrock 4) Wellhead protection & general water quality issues

– Iron & manganese – Chlorinated Solvents and other Haz Waste constituents – Petroleum leaks – MTBE – Radon & other radioactive isotopes – Arsenic

5) Modeling saltwater intrusion 6) Impact of well withdrawal on stream flow

1971

Finding exploration targets in sand & gravel

Geophysics becomes a major Tool 1980s

• Finding bedrock troughs – Seismic refraction – Gravity

• Finding S&G under clay and tracing conductive contaminant plumes – Resistivity – Terrain conductivity

• Finding basalt dikes (which are often high-yield zones) – Magnetics

• Finding high yield bedrock fracture zones – Seismic refraction – Directional terrain conductivity – VLF – Borehole Geophysics

The interpretation of pumping tests 1970-1995

• The Johnson Groundwater & Wells emphasized Thiem for steady state and straight-line approximations for non-steady flow; I used these up to 1976

• I have been using the non-steady curve matching techniques of Theis, Hantush-Jacob and Boulton since 1976; they are more informative than the linear methods

• In the mid-1980s the methods for evaluating fracture flow in petroleum reservoirs were interpreted for groundwater hydrology by folks like Gringarten, Karasaki and Neuman. I have used these methods to gain a better understanding of bedrock fracture flow

• Since 1995—beyond the usual pumping test analyses—I usually also calibrate 3-D flow models around pumping test data, which gives a much better insight into the permeability distribution around a well, which leads to a more accurate wellhead protection plan

Wellhead Protection Method based on Groundwater Travel Times

• In a 1988 paper for DEP/DHHS I suggested that the best way to protect groundwater wells was to restrict land uses within certain times of groundwater travel around the wells. This approach was accepted and is still in use.

• Before MODPATH was available to me, I used the MOC 2D model in an inverted mode (“spiked” water going into the aquifer at the pumping rate) to see how far the contamination front traveled in 200 and 2500 days.

• Once I had mastered MODFLOW and MODPATH I used MODPATH in the reverse particle tracking mode to define the zones

• I defined many travel time zones in the late 80s and early 90s, one of which was the PWD’s Chaffin Pond well field in North Windham. The Chaffin Pond aquifer was modeled with MODFLOW, including bedrock layers. The model was available when the MTBE leak occurred from a Christy’s gas station site in 1998.

Local bedrock fracture data in the area of the drilling location selected from the

lineament analysis

Enhanced 2-meter DEM for Isle au Haut. The island surface is heavily forested with spruce so without the ability to penetrate the forest canopy, one could never create this “bare earth” model. A lot of bedrock structural information can be interpreted from this DEM. When combined with field mapping of the bedrock exposures, zones of high transmissivity can be interpreted with reasonable accuracy.

Use of pressure transducers and pumping tests to evaluate continuity of sand layers between till & glaciolacustrine strata.

“Resident Farmer” Scenario Evaluations

A cross section through the Deerfield River valley where the nuclear plant sat and leaked tritium to the groundwater.

SeaWAT2000 model enabled the planning of wells and septic systems on a coastal peninsula in Islesboro

Mg/L

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Cumulative Precipitation, E-T, and Stream Discharge in eastern coastal Maine

Bear Bk cumdischarge

Calc E-T

Total Precip

Bear Br watershed = 0.04 sq. miles

Final example: Determining the impact of well withdrawal on streamflow

E-T calcs based on Penman-Monteith method

See my paper in 2013 MWC

Prediction of the impact of a pumping well on stream flow reduction

How have costs changed?

• I don’t have my old files before 1998 so can’t do too much quantification. I do recall my billing rate history and the overall costs for modeling on complex projects

• My billing rate increases kept me ahead of inflation; glass ceilings at times at $100/hr and then $200/hr; 2000 tech stock bust and 2008 mortgage derivative crises slowed down increases in the 2000’s

How have other costs changed per unit of work done?

• Prelim problem analysis—much less than inflation (shift from field work to desk-top analyses with GIS and computer databases)

• Drilling probably stayed near inflation • Laboratory testing costs increased less than inflation • Field data acquisition (much more data gathered but at lower unit

cost with things like dataloggers) • Modeling (modeling much more complexity at lower unit costs;

complex 3-D fate and transport model at San Onofre, CA in 2011 for same $ as 2-D model of simple Topsham sand plain in 1980); high modeling costs today occur when there is a lot of data to calibrate with

• Project management: costs probably increased faster than inflation rate due to increase in QAPP requirements, more recognition today of the need for good project management, and more data to acquire and manage

Summary

• 44 years—don’t they go by in a blink! • Success came from a good education, hard work, continual learning, and

being the first kid on the block to do new things • Since 1970 there have dramatic improvements in field methods and

computer capabilities • There has been a shift from doing basic field mapping at the start of a

project to desktop analysis, compiled in GIS • Computer modeling has increased dramatically in complexity. Overall

costs have not increased, even before adjusting for inflation, due to more capability, but the amount of data we deal with today is far greater than in the past, offsetting some of the savings from better software and faster execution

• My career has been very challenging and rewarding and largely built around being the first to do many things with groundwater in Maine. I built a very capable team in the period 1985-1995 and we learned a lot together and had a lot of fun.

• Notice that this talk did not contain a single equation!