SURFACE WATERS The surface streams are for the most part small and subject to great seasonal variation in the amounts of water they carry. All are liable to surface contamination and none is utilized as a source of supply. Some water powers are developed along Patapsco River which forms the northeastern boundary of the county, and along the Patuxent which forms the southern boundary of the county. This is particularly true at Ellicott City on the former stream and at Laurel on the latter. Small water powers are also utilized for milling on various small creeks in the western part of the county. UNDERGROUND WATERS Artesian Waters But few artesian wells have been drilled in Howard County since there are no large centers of population or industries requiring large amounts of water. The abundance of springs and the usual productiveness of shallow dug wells have obviated the necessity of seeking at greater depths water for domestic and farm purposes. All of the deep wells in this area derive their water from crystalline rocks. In such rocks the water occurs in fractures, joints, and faults. Since the rocks are much folded and these various water fissures enumerated do not occur in a uniform or continuous manner it is entirely impossible to forecast the artesian prospects in this area. There are no deep wells in the county, the deepest being the 306-foot well at Doughoregan Manor and the 265-foot wells of the Ellicott City Water Company. These all derive their water from the granite, have a head from within 5 to 15 feet of the surface and pump from 25 to 50 gallons per minute. Non-Artesian Waters SPRINGS. Springs are generally distributed throughout the county and are frequently utilized locally. None of large size has been reported. The water usually carries varying amounts of mineral matter. SHALLOW WELLS.-Dug wells are in general use for domestic purposes. These range in depth from a few feet to 70 or 80. Water can usually be obtained at the contact of the weathered surficial materials with the underlying hard rock. Outside of the towns, if care is taken to locate wells so that they will not receive drainage from outhouses or barnyards, the water is potable. Shallow wells are always dangerous, however, in even small centers of population since it is practically impossible to prevent contamination. MONTGOMERY COUNTY The surface features of Montgomery County are similar in character to those of the adjoining county of Howard and the other Maryland counties along the eastern border of the Piedmont. The surface is a much dissected, rolling upland, ranging in elevation from between 200 and 300 feet along the eastern border to over 800 feet in the northern part of the county where Parr's Ridge enters the county from the northeast and gradually sinks to the general level of the western part of the county which is between 400 and 500 feet. From Seneca to the bend of the Potomac at the mouth of the Monocacy the country is underlain by the sandstones of the Newark formation, and this area is both flatter and lower than elsewhere in the county and seldom reaches 400 feet. GEOLOGY The unconsolidated sands and clays of the Lower Cretaceous cover disconnected areas along the eastern border of the county adjoining Prince George's County. The western part of the county from Seneca to the Frederick boundary on the Potomac is underlain by the red and gray sandstones and shales of the Newark formation of Triassic age. Elsewhere and including the major portion of the county the underlying rocks beneath the surface mantle of soil are granites, gneisses, serpentine, and basic and acid volcanic rocks of great age and highly crystalline. These are much crumpled, and while underground waters are plentifully stored in joints and fault planes, they occur in no regular or predictable position, and it is therefore impossible to predict the artesian prospects for areas of this kind. SURFACE WATERS The surface streams are small and subject to great seasonal variation. All are liable to surface contamination and should not be utilized for domestic or municipal supplies, except where they are subject to scientific filtration. The two larger streams are the Patuxent, which forms the Howard boundary, and the Potomac, which forms the southern boundary. The latter carries large amounts of water and develops extensive water power at Great Falls and elsewhere in the county. The former is utilized to some extent for water power and small developments are utilized for milling operations on various small streams throughout the county. The public supply of Washington is taken from the Potomac at Great Falls. UNDERGROUND WATERS Artesian Waters There are no large centers of population or manufacturing enterprises requiring large amounts of water, so that throughout much of the county the inhabitants utilize springs and shallow dug wells for domestic purposes. The number of artesian wells that have been put down is small and none reach great depths. The yield and head vary through wide |