Part II – Ductile and Brittle Faulting Found at the Pole Canyon Limestone Upper and Lower Plate Boundary in Miller Basin
Large regions of penetratively stretched Upper Precambrian to Lower Cambrian metasedimentary rocks and yet undated granitic plutons are exposed in the NSRD. Lithologic contacts and foliation within the lower plate rocks are structurally concordant with the NSRD’s slightly sloped dome that proceeds alongside the top portions of Lower Cambrian Pioche Shale. This stands in direct contrast with the upper plate’s Middle Cambrian to Permian and Tertiary layers broken and tilted by imbricate normal faults that do not cut into the NSRD (Miller, Gans, Garing; pg. 242).
The structural sections that “young to the west” are repeated to the east along eastward dipping faults. These sections contain westward dipping older faults that usually are missing some units. The younger faults space apart from one km, dip 10-20 degrees to the east, and eventually merge with though do not offset the NSRD. The older faults are spaced apart at less than one km, dip 10-30 degrees to the west and are ended by either younger faults or the NSRD (Miller, Gans, Garing; pg. 243).
The upper plate shows a variety of bedding attitudes. Though most strata layers strike N10E to N45E and dip NW, the tilting amounts can range from 0-90 degrees and beyond, to the point of being overturned. Nearby faults or in incompetent units bedding plane tilts are usually low, though becoming steeper moving away from fault planes, with the steepest west facing dips found in the more massive limestone units located between faults spaced widely apart. These steepest dips are the only ones that reveal the total amount of rotation towards the west and the initial angle of bedding plane to relative to fault (Miller, Gans, Garing; pg. 243).
The Miller Basin region shows a more complex faulting where domains of conjugate, down to the west faults and SE tilting happen and also domains of down to the east faults. Strike-slip fault zones with high angles separate the domains of opposite tilting. To the south of Miller Basin, the faults become more distant from another while there is a sudden decrease in the total amount of extension (Miller, Gans, Garing; pg. 243).
Within the lower plate the metasedimentary rocks are of amphibolite grade and the metamorphism increases both with depth and towards the north. There is a younger penetrative subhorizontal foliation and lineation rising in intensity moving both upwards and eastwards towards the decollement overlaid on all lower plate metamorphic and igneous rocks. The farthest west exposure of the lower plate’s Prospect Mountain Quartzite the foliation and lineation are poorly formed, while the NSRD’s eastern flank strata units that were once 3 km thick have been ductiley thinned to less than 0.5 km thick. Both the basal section of Pole Canyon Limestone and very attenuated and mylonitic parts of Pioche Shale are found throughout the decollement as extremely thin layers. Though lower plate strain decreases further away from the decollement, it doesn’t stop within the current exposure levels. The original thickness and strain of the McCoy Creek Group rocks are not known, the distance down to the Precambrian crystalline basement rock is also unknown (Miller, Gans, Garing; pg. 248).
The NSRD has a very sudden fault break between brittlely and ductilely deformed rocks. Pole Canyon Limestone is present both above and below this fault nearly everywhere throughout the NSRD. The NSRD gives an example of an exhumed mid-Tertiary ductile-brittle transition zone provided that the stretching of the lower plate was synchronous with faulting of the upper plate. Intermittent sections of ductile deformation and recrystallization found in the lower sections of the upper plate fault slices (ex. Pole Canyon Limestone) show a relatively dispersed evolution. The extension proceeded with the transition becoming quickly localized inside a tapered (5m across at multiple levels. Probe to rockhead, prove rock to 5m with splayed probes, microgravity survey bored piles to rockhead or cap grouting at rockhead, control drainage and abstraction.
5) kV Extreme – NSH >>1 Formed only in the wet tropics. Has very large sinkholes of all types, remnant arches, soil compaction in buried sinkholes. Rockhead has tall pinnacles with relief of >20m, loose pillars are undercut between deep soil fissures with abundant and very complex dissolution cavities, numerous complex 3-D cave systems with galleries and chambers >15m across. Make individual ground investigation for every pile site, bear in soils with geogrid, load on proven pinnacles, or on deep bored piles, control all drainage and abstraction.
They also point out that a desert class ‘kl Juvenile’ karst may have almost no contemporary dissolutional development, though it may have large unseen caves left over from earlier climates that were wet and tropical (Waltham). This needs to be included in the karst class, described as k1 Juvenile containing pockets of kV Extreme. In the Snake and Spring Valley, this occurs nearly across the entire aquifer system. Most of the large karst caverns from Lehman caves to the aquifers beneath the valleys were not formed during desert conditions as the climate during formation was wetter and warmer, between temperate and tropical. The combination of warm temperatures and greater amounts of precipitation bringing acidic carbonic acid rainwater into contact with the ancient karst rockhead of the Snake and Spring Valley aquifers resulted in the current large caverns that are capable of storing large quantities of groundwater.
Waltham and Fookes state in their recommendations for karst classes kIV – kV that control of abstraction is needed to maintain the karst system’s structural integrity (ie., prevent subsidence, collapse, etc…). Engineers in Florida recognize a potential and probable geohazard when new sinkhole failure rate is greater than 0.1 per km2 per year. However, sinkhole frequency is not a dependable reference for karst classification as the rate increases in places of either thin soil cover or groundwater lowering (Waltham).
Karst classification should include karst class, sinkhole density, cavern size, rockhead relief and whether the material is limestone or gypsum. Sinkhole density should include number per unit area and their size in diameter. The rate of new sinkholes (NSH) is measured per km2 per year. The NSH rate will be higher in karst regions with thin soil cover and can also be temporarily raised by engineering activities (Waltham).
It is difficult for geologists to find underground caverns who often depend on closely spaced probes to find any. Usually a density of 2,500 probes per hectare is required to have a 90% chance of discovering a cave at least 2.5 meters diameter. Probing beneath every column base and pile foot usually is more reliable and often needed for mature karst. Probe depth should be similar to expected cave size. For karst classes kI – kIII, caves greater than 5 m wide are not often found, so a 3.5 m probe should be adequate. In karst class kIV caves are usually near 10 m wide, needing a probe of 7 meters. The largest caves are often found in karst class kV (Waltham).
To prevent sinkhole failures from occurring, it is important to control water flows and abstraction. At Florida’s Disney World, wells are monitored so that pumping is switched whenever a lowering of local groundwater levels is noticed (Waltham). The common factor between over-abstraction or excessive removal of groundwater in either limestone or low grade marble karst aquifer systems is eventual subsidence of land and loss of aquifer capacity. Karst caverns are enlarged only if they are filled with acidic carbonic acid rainwater, they do not enlarge from removal of water. The removal of water from karst caverns results in lowering of cavern roof towards cavern floor and overall loss of future water storage space.
The same process of aquifer overdraft will happen in the Snake and Spring Valley aquifer system if the SNWA gets their way and builds this proposed pipeline. The karst classes are like grades of marble, each one varies in strength and ability to withstand fracturing at stress points. Two different types of karst layers with two varying strengths can exacerbate this instability by causing the more fragile shale rock to collapse into the limestone strata below.
More Reasonable Water Acquisition Methods for Las Vegas Valley than the Snake/Spring Valley Pipeline
The most reliable source of water for the Las Vegas Valley remains the Colorado River at Lake Mead. The concerns positioned by the SNWA about Las Vegas “running out” of water because Lake’s levels are lower than average are overly exaggerated and possibly a feeble excuse to build massive infrastructure projects like the SNWA pipeline from Snake/Spring Valley aquifer system for the sole benefit of suburban sprawl developments like Coyote Springs. The amount of profit from building over 100,000 houses is enough incentive for SNWA beneficiaries to endorse an otherwise cumbersome, expensive and overall unreliable source of water for their ratepayers.
The concerns expressed by SNWA are that the lake levels are too far below the intake valves where water enters the system for purification. However, there is a much simpler method of overcoming this obstacle than building an expensive pipeline that would eventually be unusable. Designing a simple flexible tube similar to a bending straw that can be extended from the intake valve, curved 90 degrees and then lowered to the lake level where an electric powered vacuum pump would lift the water up would be more effective and cost SNWA ratepayers far less. It is highly improbable that Lake Mead would ever dry out entirely as there will always be some amount of inflow from the Colorado River even in the driest season. If the least likely scenario of dam failure were to occur, there would still be time to rebuild a temporary dam and harness any Colorado River water that passes through the steep canyon underneath the intake valve hoses that could be lowered as far as needed until water level is reached. This lowering curved straw tube would be an enhancement to the current system of intake valves that depend upon the Lake remaining at a certain level. The lowering curved straw intake tubes prevent crisis from occurring during a several year drought period when the Colorado River watershed receives less than expected precipitation for several years duration.
It should be stated that there is no current crisis as a season of heavy above average precipitation has restored Lake Mead’s levels from the recent drought of several years. It is not ironic that the SNWA public relations team has played up this recent drought as a reason the pipeline was so desperately needed even though only one season of above average precipitation has ended a drought of several years. The existence of Las Vegas has relied nearly entirely upon Lake Mead’s water for several decades without any threat of or actual interruption of access. Over the last few decades the water usage per person has declined, so why the sudden urgency for this pipeline in the last decade?
It seems apparent that there is no real need for the pipeline from the Snake and Spring Valley and there is some unethical activity afoot behind the scenes at the SNWA boardroom where their authority is being wielded unjustly against the residents and ecosystems residing above the two targeted aquifers. It is unfortunate that developers are making short term choices that effect the ecosystems that depend upon the aquifers. Excessive groundwater withdrawal for golf courses, lawns and other lifestyle choices transplanted from regions with greater amounts of rainfall can compact sediments, reactivate old faults, and cause surface fissuring (Bell).
The main beneficiaries of the SNWA’s proposed pipeline include developers like Harvey Whittemore who would benefit from promises of future water along the nearby pipeline. Developers who cash in now and sell their homes to unsuspecting owners can cash in early and retire rich before the aquifer is depleted and the pipeline rendered useless. However, for the sake of argument, if there were a longer drought what are some additional ways that Las Vegas Valley can be more efficient with their limited water supply?
Other options for accumulation of water during summer rainstorms would benefit Las Vegas Valley residents in two different ways. Rainwater can be collected from rooftops with rainwater harvesting systems and filtration following collection. Any extra rainstorm surplus stored belowground would benefit the local aquifers that were left overdrafted for years. The additional side benefit of rainwater harvesting is that during summer rainstorm events when the majority of the region’s precipitation falls, the rainwater collected from rooftops would be less runoff water that leads to flash flood events.
Las Vegas Valley is notorious for their summer rainstorms dumping nearly the full year’s amount of rainfall in just a few hours storm. Several inches of water in under an hour all running off into the streets often causes severe flash flooding events that causes loss of human and animal life along with property damage. This sort of rainfall pattern is normal in summer months for the desert climate may become more intense from global warming sea temperature rising (Haro).
During the summer storms the torrents of rain often drop from 35 – 75% of the total 4.13 average annual rainfall from 60-90 minutes. During a storm on July, 8 1999 a heavy downpours overwhelmed the flood basins, killing two people and caused over 20 million dollars property damage. The location of the Las Vegas Valley between the Sheep and Spring Mountains combined with the impermeable nature of the caliche (Calcium Carbonate) soils make the Las Vegas Basin prone to flash flooding. Urban development and roadways above former alluvial fans only worsen the severity of the flooding events (Haro).
The runoff from rainstorms either settles into puddles on hardpan where it evaporates or enters the Las Vegas Wash that enters Lake Mead. Although it seems there is no net loss, the transport of water through the Las Vegas Wash still loses a percentage to infiltration into the sands of the wash channel and extra losses from evapotranspiration by the mesh of water loving trees that line the wash channel. The trees of Las Vegas Wash were not there in such large numbers until after there was yearly water flowing through the channel that was previously a dry wash for most of the season. By intercepting the summer rainstorms with rainwater harvesting technology, the net loss of water from evapotranspiration through the Las Vegas Wash and losses from hardpan puddle evaporation can be eliminated and every drop of stormwater will be stored in cisterns beneath the ground.
Instead of depriving Northern Nevada’s ranchers of their livelihoods by taking out their aquifers one by one like a water thirsty serial killer, the SNWA could instead help provide the Las Vegas Valley with sustainable green jobs by being innovators of new and exciting rainwater harvesting systems designed for personal home use and also large industrial buildings and casinos. There are rainwater harvesting systems designed specifically for large buildings with greater rooftop surface area for capturing rainfall. For larger rooftop areas, the filtration system needs to accommodate for excess flow. System can be designed by building three circular chambers where the outer chamber is filled with sand, the middle one with coarser gravel aggregate and the inner-most layer with pebbles. This would increase filtration area for the sand, with relation to the coarser aggregates and large pebbles. Rainwater eventually reaching the central chamber would be collected in the sump and finally treated with chlorine and ready for safe drinking. (Rainwater Harvesting, R Jeyakumar)
In Alex Steffen’s book titled “Worldchanging” he discusses the benefits of rainwater harvesting and storage in underground cisterns was used for thousands of years. Considering the book’s foreward is written by Al Gore one would think a learned Democrat like Sen. Harry Reid would follow the advice of his peer and encourage sustainability by promoting rainwater harvesting instead of looking the other way when the SNWA promotes treating aquifers as if they were disposable plastic cups with their pipeline (Manaugh).
The book also discusses options to transport water from regions with surplus supplies such as the Midwest, especially along the flood prone Mississippi. This is heading in a logical direction as these are often regions with surplus water and large scale river flooding events, whereas the Snake and Spring Valley aquifer output is never in surplus and is often below what it should be. Recharging aquifers with flood surplus water is the way to shore up reserves for potential drought years.
In a hypothetical future Midwestern flood event the use of setback levees and settling ponds along river floodplains could be used to store excess flood water. Setback levees are further away from the riverbed and enable larger volumes of water to spread out and thus reduce pressure on the levees. Sacrificing some portion of land to set the levees further back and give the river more room to roam in a flood event would save everyone from a catastrophic flood. During these flood events the water stored in settling ponds could be transferred by tanker trucks to rail cars and then taken to Las Vegas to be injected into the aquifer for storage.
The SNWA’s proposal to extract 41 billion gallons per year from the Snake and Spring Valley aquifer system would show a probable result of eventual groundwater overdraft, land subsidence, dried out springs and eventual extinction of spring dependent endemic species such as spring snails. This can be determined by comparing the rate of aquifer recharge from a wetter prehistoric climate with far more yearly precipitation to the current rate of recharge in the modern desert climate to the SNWA’s proposed rates of extraction by the pipeline. The numbers do not ever balance out, the current rate of recharge is nothing near the initial rate of recharge during the far wetter climate and the proposed rate of extraction will overwhelm the stored reserves in mere decades.
The subsidence in the Pahrump Valley and around Las Vegas Valley from extractions begun decades ago shows this dysfunctional habit of taking from aquifers until they are overdrafted to a point beyond repair. The evidence shown from previous aquifer drawdowns and resulting species extinctions of spring dependent endemics such as the Las Vegas dace and the Vegas Valley Leopard Frog is that the pattern of overdrafting groundwater is pathological for a society that is otherwise able to learn from their mistakes. Earlier mistakes that caused extinctions by drying up springs may have been out of ignorance, though today the SNWA no longer has this excuse. The pattern of aquifer overdraft based upon perpetual suburban sprawl development in desert regions is pathological behavior and needs to cease for the greater good of the ecosystem. In this situation the pathology is not gambling or other so-called “vices” that the Las Vegas Valley is known for, but the overconsumption of groundwater needed by the encroachment of poorly planned suburban sprawl developments, golf courses and other needless luxuries demanding ever greater inputs of water than the surrounding desert ecosystem is able to provide.
This report has shown evidence of the earlier extractions from aquifers near Las Vegas and the Pahrump Valley resulting in land subsidence and also loss of springs and seeps. The loss of the groundwater’s surface exit through springs and seeps at specific elevations caused endemic species such as the Vegas dace and the Vegas Valley Leopard Frog to become extinct. These extinctions could have been prevented had groundwater levels been maintained at their highest possible levels so that the seeps and springs were always guaranteed to remain viable habitat for endemic species that depend upon the water for their very survival.
Further details from the sediment fill aquifer in Pahrump Valley and limestone aquifers in Florida show common repeating patterns of overdraft, subsidence and sinkholes as the final result. These and other examples of aquifer overdraft throughout the U.S. show that the problems of groundwater overdraft are not limited to Nevada. This common trend of overdrafting aquifers and the resulting effects of subsidence and loss of springs occur regardless of the type of aquifer substrate as the same force of gravity pushes down on the overburden and forces the land formerly above the aquifer to a lower position. Without any upward directional buoyant support from the groundwater there is nothing else to prevent the force of gravity from pushing the material above down into the aquifer space below that was previously occupied by groundwater.
The three detailed studies of the northern Snake Range decollement (NSRD) highlighted in this report show the incredible complexity of strata with faulting at many different angles, brecciation and boudinage. The studies show strata of upper and lower plate rocks interacting along the boundary between Lincoln Peak Limestone (LPL) and Cambrian Pole Canyon Limestone (PCL). The position of the LPL and PCL strata is along the boundary between the upper and lower plate rocks, effectively cutting the aquifer holding strata layers into two components that operate independent of one another with respect to movement. This already existing geological instability would be worsened by the caverns being dewatered by SNWA pipeline extractions as less counter-gravitational support from water can cause more fracture prone stress points vulnerable to collapse during any future movements along the plate boundary.
In comparison with other layers the PCL karst strata primarily responsible for forming aquifer caverns is relatively thin and cannot be expected to last for long at the SNWA’s proposed rate of 41 billion gallons per year for more than two decades. Even at far lower rates of extraction than those proposed by the SNWA the aquifer would not be capable of lasting longer than three decades due to significantly lower rates of recharge when compared to precipitation amounts during the time of formation. Even the current extractions by local ranchers are having a detrimental effect on the aquifer, indicating that there is not a drop of water to spare. The most effective way to protect the Snake and Spring Valley aquifer system is to limit extractions to where water can be returned to the same aquifer drainage basin from where it was initially removed from.
Removing groundwater from the Snake and Spring Valley aquifer system and transporting it 300 miles away will cause irreparable harm to the caverns by suddenly dewatering them. The long term result of the SNWA pipeline extracting groundwater from the Snake and Spring Valley aquifer system will be land subsidence, reduction of aquifer capacity, loss of springs causing extinction of endemic species and finally a useless 300 mile long pipeline paid for by the working people of urban Las Vegas.
When examining the NSRD strata layers and their neighbors, it appears that several types of limestone, dolostone, shale and marble of various grades of strength all share nearly the same level and interact with one another often. Since the aquifer system is not confined to one basin, the removal of large amounts of water as proposed by the SNWA would effect every part of the aquifer and not just be confined to the location of drilling. If one region of the aquifer is dewatered, it will effect other locations also. The outcome of lowering groundwater levels in this aquifer system is uncertain, based upon the instability and fracture potential of different grades of marble, limestone, dolostone and shale all located nearby one another.
The thesis paper by Cal Poly student Johnston examined the nature of faulting throughout the NSRD and concluded a “rolling hinge” model of faulting is the most appropriate description model for the process. The new model differs from earlier “falling domino” models by showing a spiderweb network of faults originating from a central axis point of a main fault pushing from west to east. The network of faults displaces tension between the faults by stretching the rocks out along the rolling hinge. However, the rolling hinge of fault networks also would create more stress points vulnerable to fracture if there is removal of counter-gravitational support from the groundwater below. Many of these rolling hinge faults cut into the Pole Canyon Limestone where the aquifer caverns are located. With the complex network of faults connecting to and splaying out from the axis of the rolling hinge there are infinite stress points vulnerable to fracture if there is removal of counter-gravitational support once supplied by the groundwater.
Research highlighted the importance of protecting and maintaining aquifers and groundwater levels to their fullest potential. The facts show that removing excessive water from aquifers not only dries up seeps and springs that provide crucial habitat for endemics such as spring snails, it also can reduce the future capacity of the aquifer to hold groundwater by lowering the elevation of the cavern ceilings following land subsidence. By keeping aquifers at their fullest potential, the storage capacity will be increased as the pressure of the groundwater will be in all directions, causing the fissures and fractures to expand from dissolution. This reflects the ongoing pattern of karst cavern formation from contact with pressurized groundwater.
The political and financial aspirations of Harvey Whittemore’s Coyote Springs development with the additional 100,000 homes planned and their relationship to the pipeline should be investigated. The potential for making between 20-30 billion dollars from the planned homes would be enough incentive for the SNWA to work with Mr. Whittemore behind the scenes to make the pipeline a reality. However, this plan would only benefit the few developers and SNWA bureaucrats who would profit the most from the pipeline while the working people of urban Las Vegas will shoulder the financial burden as ratepayers and the spring ecosystem endemic snails will suffer the penalty of extinction.
It could be reasonably estimated that the Snake and Spring Valley aquifer will be overdrafted beyond repair in only a few decades if the SNWA’s proposed extraction amounts occur. This would result in the abandonment of the pipeline for only a few decades worth of water. However, it would be ample time for the developers at Coyote Springs to provide their 100,000 new homeowners with promises of pipeline water until their retirement.
Alternative means of harnessing water such as rooftop rainwater harvesting, additional conservation, landscaping with drought tolerant plants and a “bending straw” extension with a pump attached to the intake valves at Lake Mead should be able to provide enough water for all even in the worst drought years. Rooftop rainwater harvesting would also provide additional benefits of flood control by removing an amount of stormwater based on the rooftop’s area size from the overall net runoff stream and diverting it to underground cisterns for future uses. This report shows that these options are far more cost effective, reliable and safer for ecosystems than is extracting groundwater from distant aquifers that do not contain enough water to last for more than a few decades.
“Cave Geology in Depth: In Depth Geology of Lehman Caves”
Center for Biological Diversity Press Release; Rob Mrowka and Tierra Curry, 02/09
“Engineering classification of karst ground conditions” by Waltham A. C. and Fookes P. G.; 2005
Speleogenesis and Evolution of Karst Aquifers; re-published from the Quarterly Journal of Engineering Geology and Hydrogeology, 2003, vol. 36, pp. 101-118.
“Geology of the Spring Mountain Quadrangle, Nevada and Utah” by Phillip B. Gans, Elizabeth L. Miller, and Jeffrey Lee; Text and references to accompany NBMG Field Studies Map 18
“Ground Water Atlas of the United States”; California, Nevada, HA 730-B
“Groundwater: the Invisible Resource” from World Water Day on 22 March 1998, organized by United Nations Division of Economic and Social Affairs (UNDESA), UNICEF
Johnston, SU; Cal Poly Thesis
“Karst Breakdown Mechanisms from Observations in the Gypsum Caves of the Western Ukraine: Implications for Subsidence Hazard Assessment” written by Klimchouk A.B., Andrejchuk V.N., 2003, Speleogenesis and Evolution of Karst Aquifers Vol. 1, Issue 1
“Las Vegas Valley: Land Subsidence and Fissuring Due to Ground-Water Withdrawal” by John W. Bell Nevada Bureau of Mines and Geology
National Geological Map Database “GEOLEX database, Geologic Unit: Pole Canyon” published by United States Geological Survey
North Carolina Division of Water Resources, Raleigh, NC 27699-1611
Phone: (919)733-4064 - Fax: (919)733-3558
“Phylogenetic Relationships” by Spring Snail Center Researcher: Hsiu-Ping Liu, Rocky Mountain Center for Conservation Genetics and Systematics
Collaborator: Dr. Robert Hershler, National Museum of Natural History; Smithsonian Institution
Rainwater Harvesting “Components of a Rainwater Harvesting System” system designed by R Jeyakumar
“Sin City Goes Dry” by Ted Williams, Audubon Magazine; March/April 07
“Subsidence in Las Vegas Valley” (Spring 1994) by Donald C. Helm, Research Hydrogeologist
Nevada Geology: Quarterly Newsletter of Nevada Bureau of Mines and Geology
“The Sixth Extinction; Current Biodiversity Crisis” information website by Peter Maas, Administrator Netherlands
“Sinkhole.org” public information website by Michael D Mosher; Administrator 866-999-SINK (7465)
“Tales of French Fries and Bottled Water: The Environmental Consequences of Groundwater Pumping”
By Robert Glennon; Issue 37:1
“The Snake Range Decollement: An Exhumed Mid-Tertiary Ductile-Brittle Transition” by Elizabeth L. Miller, Phillip B. Gans and John Garing; Department of Geology, Stanford University; Stanford, CA 94305
Published in Tectonics; Vol. 2, No. 3, Pages 239-263; June 1983. http://www.colby.edu/academics_cs/courses/GE398/upload/Miller-et-al-1983.pdf
“The Las Vegas Flash Floods of July 8, 1999: A Post-Event Summary” by Jesus A. Haro, Harold R. Daley, Kim J. Runk - NWSO Las Vegas, Nevada
Western Region Technical Attachment; No. 99-26 November 9, 1999
“Water Resources & Aquifers of The Great Swamp” by Russell Urban-Mead M.S., presented to The Great Swamp Watershed Conference on October 4, 1997
The Chazen Companies September 15, 1997
“Water, the New Oil” by Geoff Manaugh published in Next American City Magazine Issue; Summer ‘07
other info websites;