Geology for Environmental Planning in the Burlington-Middlebury Region, Vermont

GEOLOGY FOR ENVIRONMENTAL PLANNING IN THE BURLINGTON-MIDDLEBURY REGION, VERMONT B ' DAVID P. STEWART VERMONT GEOLOGICAL SURVEY Charles G. Doll, Stale Geolagist WATER RESOURCES DEPARTMENT MONTPELIER, VERMONT ENVIRONMENTAL GEOLOGY NO. 3 1973 TABLE OF CONTENTS Page INTRODUCTION ..................... 7 SOURCE OF MATERIAL .................. 8 EXPLANATION OF PLANNING MAPS ............. 10 GEOLOGIC SETTING ................... 12 Champlain Lowland .................... 12 Green Mountains .................... 14 Environmental Significance of Structure ............. 1 7 DRAINAGE ....................... 17 BEDROCK ....................... 19 Rocks of the Champlain Lowland . . . . . . . . . . . . . . . I Rocks of the Green Mountains ................. SURFICIAL MATERIAL ....................... SURFACE WATER ..................... 3 GROUND WATER .................... 24 SOLID WASTE DISPOSAL ..................32 SEWAGE DISPOSAL ...................... FOUNDATION MATERIAL ................. 35 GEOLOGIC HAZARDS ................... 36 Landslides ....................... 36 Flash Floods ...................... 37 GEOLOGIC RESOURCES .................. 37 Sand and Gravel ...................... 7 Crushed Stone ..................... 39 Dimension Stone ...................... 9 Talc ......................... 40 Lime ......................... 40 Kaolin ......................... 41 ACKNOWLEDGMENTS .................. 42 REFERENCES CITED ................... 43 REFERENCES FOR PLANNERS ................ 44 APPENDIX A—MAPS SHOWING LOCATIONS OF SEISMIC PROFILES. 45 LIST OF ILLUSTRATIONS Page FIGURE 1. Index map showing regions where environmental studies have been completed ................. 6 FIGURE 2. Index map showing the location of quadrangles, townships, cities and villages in the Burlington-Middlebury region . . . 9 FIGURE 3. Cornfield inundated by water, July, 1972. Clay soil could not absorb water rapidly enough during wet summer season. Four miles west-southwest of Addison ........... 10 FIGURE 4. Geomorphic subdivisions and major topographic features of the Burlington-Middlebury region .......... 11 FIGURE 5. Eastward dipping beds of limestone marble exposed in a quarry two miles east of Shelburne ............. 12 FIGURE 6. Snake Mountain rising conspicuously from the Champlain Lowland. Quartzite and dolomite rock are exposed along the crest. Picture taken looking east from Dead Creek, two and one- half miles southwest of Addison ...........13 FIGURE 7. Small solution cavern at the contact of the Hinesburg thrust at Mechanicsville. Complex rocks of the Green Mountains (above) thrust over dolomite of the Champlain Lowlands .....13 FIGURE 8. White quartzite bedrock exposed on the west slope of Hogback Mountain four miles north of Bristol ..........15 FIGURE 9. Fractured limestone marble exposed in a quarry two miles north of Brooksville ...............15 FIGURE 10. Camels Hump from Interstate Highway (1-89). Picture taken looking southwest three miles east of Bolton . 16 FIGURE 11. Drainage basins of the Burlington-Middlebury region. 18 FIGURE 12. Bostonite dike in limestone marble exposed in a quarry two miles east of Shelburne . 20 FIGURE 13. Solution weathering of limestone marble two miles east of Shelburne ..................21 FIGURE 14. Fractures in dolomite marble enlarged by solution weather - ing. Three and one-half miles north of Bristol . 21 FIGURE 15. Lacustrine beach gravel exposed in a pit one mile southeast of Waitsfield . 23 FIGURE 16. Northeast-southwest seismic profile across a portion of the Winooski Valley at Waterbury ............ 26 FIGURE 17. Northeast-southwest seismic profile across the Winooski River valley two and one-half miles northwest of Richmond. 27 FIGURE 18. Northeast-southwest seismic profile across the Winooski River valley one-fourth mile east-southeast of North Williston . 27 FIGURE 19. Northwest-southeast seismic profile across the Mad River valley one and one-half miles south of Irasville ........ 27 FIGURE 20. Northwest-southeast seismic profile across the Mad River valley one and one-half miles southwest of Moretown ...... 28 FIGURE 21. East-West seismic profile across the Huntington River valley one and one-fourth miles south of Huntington Center. 29 FIGURE 22. East-West seismic profile across the Huntington River valley two and one-half miles north of Huntington village ...... FIGURE 23. East-West seismic profile across the Huntington River valley in the village of Huntington ............. 29 FIGURE 24. Northeast-southwest seismic profile across the La Platte River valley one-fourth mile south of the village of Hinesburg. 29 FIGURE 25. Seismic profile trending southeast-northwest across the Lewis Creek valley two miles south of Starksboro ........ 30 FIGURE 26. East-West seismic profile across Bristol Flats two miles south- southwest of Bristol ................. FIGURE 27. North-South seismic profile across the New Haven River valley one mile southwest of New Haven Mills ......... 31 FIGURE 28. Northeast-southwest seismic profile across Beaver Brook valley two miles north of Ackworth ............ 31 FIGURE 29. The Weybridge Slide shortly after it occurred in February, 1956. Note road bed and signs at bottom and undermined farm home. Photograph by C.G. Doll, State Geologist ...... 36 FIGURE 30. The Weybridge Slide in the summer of 1972. Note foundation of house that had to be moved at upper left ....... 7 FIGURE 31. Road to the Bolton Ski Basin washed out by flash flooding in July, 1972. Two and one-half miles north of Bolton Village. 38 FIGURE 32. Gravel Pit in delta deposit one mile north of Waitsfield. 39 FIGURE 33. Pit in Kaolin deposits that was worked by the Vermont Kaolin Corporation 1961-1966. One and one-fourth miles south of East Monkton .................. 40 FIGURE 34. Kaolin stockpiled by the Vermont Kaolin Corporation 1961- 1966. One and one-fourth miles south of East Monkton . 41 PLATES (In Pocket) PLATE 1. Surficial Material of the Burlington-Middlebury Region PLATE II. Bedrock of the Burlington-Middlebury Region PLATE III. Ground Water Potential Map of the Burlington-Middlehury Region PLA1 E IV. Solid Waste Disposal Conditions cl the Burlington-Middlebury Region PLATE V. Septic Tank Conditions of the Burlington-Middlebury Region PLATE VI. General Construction Conditions of the Burlington-Middlehury Region PLATE VII. Sand and C;ra'el Reserves of the Burlington-Middlebury Region K —;A;: - Ic 7 / TROY St 0 I 7 /J QEDEN WHITE RIVER JUNCTION &/ ST Ocic Borre-Montpelier Region WINDSOR ll (Stewart, 1971) I Rutland-Brondon Region (Stewart, 972) Burlington-Middlbury Region (This Report) AANC BELLOWS FALLS t I EN(NGONJ 1LMINGTO" BqATTLEBM -1 Figure 1. Index map showing regions where environmental studies have been completed. 6 GEOLOGY FOR ENVIRONMENTAL PLANNING IN THE BURLINGTON-MIDDLEBURY REGION, VERMONT By David P. Stewart* INTRODUCTION important geologic resources should receive major consideration in the planning for future use. Fh is is i lie tlìi id report concerning a series of The regions that have been studied thus far environ mental studies sponsored by the Vermont were chosen because of the growth potential of those Geological Survey. The first study was completed in sections. It is unquestionably true that the Burling- the Barre-Montpelier region and a report was pub- ton-Middlebury region will be one of the areas of lished in 1971. The second survey was in the Rutland- very rapid growth in the next decade or two. The fact Brandon region and a report on this work was pub- is, expansion has already begun. Included in the lished in 1972. The present report, for publication region is the lake border of the Port Henry, Burling- in 1973, is concerned with the geology of the Bur- ton and Middlebury quadrangles, and the mountain- lington-Middlebury region (Figure 1). The purpose ous terrain of the Camels Hump and Lincoln Moun- of these reports is to describe the geology of the tain quadrangles. region concerned and to outline the geologic condi- The greatest concentration of population of the tions on a series of large-scale maps in such a way as Burlington-Middlebury region is in the area that to make the material available for use by planners. includes the cities of Burlington, South Burlington, Inasmuch as planning agencies do not usually have Winooski, and Essex Junction. Already these four geologists on their staffs, these reports attempt to centers have been growing towards one another and, supply the geologic background, in condensed and except for the Winooski River, their boundaries are simplified form, necessary for adequate planning. becoming more and more obscure. Expansion of the Geology is essential to certain aspects of environ- population has already begun beyond the limits of mental planning inasmuch as it is three dimensional these centers mostly on the lowland to the south. and therefore includes the description of subsurface The village of Middlehury is the most southern point bedrock as well as the unconsolidated surficial ma- of high population density in the region. The village terial above it. The properties of the surficial ma- is growing and expansion beyond its limits has been terials and bedrock that relate to their water holding about equal in all directions. Vergennes has also ex- capacities and the movement of water through them perienced growth adjacent to the city. But whereas is probably the most important single geological as- the population spread in the vicinities of Burlington, pect of environmental planning. The availability of South Burlington,

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