What is soil plasticity ? How does it allow you to prevent slope failures ?
Inexpensive management of surface water could have prevented the slope failures illustrated in Figure 1. The slides occurred upon a creek escarpment on the east coast of Graham Island, Queen Charlotte Forest District. Since it was harvested in the early 1990’s this escarpment has produced an estimated 50 landslides, from 20 slide zones. Slope stability investigations have revealed that the escarpment is composed of medium plastic till. The till is among the most plastic (clay-like) of the soils a forestry worker can reasonably expect to encounter along coastal British Columbia. Inexpensive management of surface water would have prevented the worst of the slope failures upon the escarpment. Had the rock quarries in Figure 2 been built to be free draining, the slides in Figure 1 should not have occurred.
Quaternary Geology of Canada and Greenland
The three major sections of this volume include six chapters describing the regional Quaternary geology of Canada, two describing the Quaternary geology and climatic history of Greenland, and six that review applied Quaternary geology in Canada, including chapters on paleobotanical analysis, geodynamics, geomorphic processes, terrain geochemistry, Quaternary resources, and the influence of the Quaternary on the present environment. Of the five accompanying plates, three depict eleven stages of Quaternary paleogeographic change between 18,000 B.P. and 5,000 B.P.; one depicts the retreat of the ice from between 18,000 B.P. and the Recent; and another reviews the status of Quaternary geologic mapping in Canada, with an extensive bibliography on the back.
The Inca Occupation of the South Coast of Peru
like the others, however; it forks into several nearly parallel ravines of which the largest are Huayuri, Rio Grande-Palpa, Ingenio (called Collao in ancient times), Nasca proper (the ancient Caxamarca), Taruga, and Poroma. Due to peculiarities of the local topography, the irrigated areas in Ica and the ravines of Nasca are located inland, at the foot of the mountains, rather than at the mouths of the rivers as is more usual in Peruvian coastal valleys. No sharp natural or cultural boundary separates the valley of Chincha from the valleys of Cafiete (ancient Huarco and Runahuana), Asia, and Mala, the next valleys going up the coast to the northwest. At the other end of the area we are considering, however, there is a sharp break; beyond Yauca the Andean foothills reach out to the sea, natural conditions are quite different, and there are important differences in the archaeological picture as well. The historical sources which mention the south coast are not particularly helpful, except in so far as they provide us with a few dates. To begin with, no chronicler gives an explicit account of the political organization of the south coast at the time it came into contact with the Incas. It can, perhaps, be inferred from Cabello Balboa's statements about common policy toward the Inca invaders that there was some sort of political connection between the valleys of Mala, Cafiete, and Chincha, but the connection need have been no more than a temporary military alliance. Cabello makes no mention at all of Pisco. The valleys of Ica, Nasca, and 125