SEWER SYSTEM OF BUTTE, MONT.
Butte, Mont. has had from the first a separate sewer system—the combined system for carrying off both storm water and hose drainage being by no means suitable for a dry climate where water for flushing purposes is scarce. The natural slope of the city reduced the problem of constructing the storm sewers to one of comparative simplicity. Butte is traversed by three well defined water courses, the Missoula, Buffalo, and Old Town gulches, and storm culverts of rubble masonry were placed where the streets intersect the gulches. The Old Town culvert is now constructed fiom the south side of Mercury street to the north side of Wyoming street; Buffalo gulch culvert from the south side of Iron street to the north side of Woolraan street. As yet the Missoula gulch culvert is buiit under four streets only. The walls of these culverts are of stone, the arches of orick, and the paving of smelter slag laid in concave form—the whole done in cement mortar. The Buffalo gulch culvert passes through the most densely populated district of the city, and it has been found absolutely necessary to keep a constant watch over it to prevent a breakage which, in the opinion of the engineer, would result In great loss of property, and, perhaps, of life.
Before the separate sewer system was built, the Buffalo gulch received the contents of house connections, drainage sinks,and closets—making it very foul. By order of the council these were all disconnected and forced to drain into the sanitary sewerage system. In 1890, two catchbasins were also constructed at the corner of Main and Granite streets. In 1893, another was built at the corner of Hamilton and Granite streets, and drains were built from them to the Buffalo gulch culvert. These have served as important adjuncts to the storm water system, and have helped greatly in cleaning the principal streets of running water.
The construction of the sanitary sewer system began in 1889. Very little work was done in 1891; but several miles were constructed in the three years following. The total length of sanitary sewers of all sizes in use at the present time is twelve and thirty-seven one-hundredth miles. There are also 150 manholes, built of brick and covered with a heavy cast iron cover. All of the sanitary sewers are of cement pipe manufactured in the city. No sewer in the city has ever been taxed to more than one-tenth of its carrying capacity and the entire sewerage of the city,which comes from 494 connections,would all flow through an eight-inch pipe on a grade of one-half foot fall each 100 feet. During the year 1894, the main outlet sewer was extended to Silver Bow creek (part of it in a wooden box) at an expense of $3,800, During 1803 additional surface sewers, and an intercepting sewer were built—the latter on Columbia street, with an outlet thence to the city dump about a mile distant at a cost for the last of $6,700.
The city now has 8,433 linear feet, or one and six-tenths miles of storm culverts,the actual cost of which has been about $97,000, at least $6,000 of which has been for repairs during the past four years. All of this sum was raised by general taxation and from the bond issue of 1889-90. In *.he opinion of the city engineer this form of public improvement is farther advanced than any other over which the city has control, and it is recommended that eight new catchbasins be built at various points in the city at a cost of $3,145.
Since 1892 and including that year,special assessments have been made against property bordering upon, and benefited by sewer construction,in proportion t2 the property frontage, and for enough to defray the entire cost of the work, including the salary of the inspector,cost of publishing the assessment roll, and ail incidental expenses connected wth its construction. The total cost of sanitary sewers to date has been approximately $127,000. The total bond issue for sewer purposes amounts to $105,000, most of which went to pay for storm sewers.