RURAL WATER SUPPLIES
Primitive Systems in Use in Northwestern Canada Community Reservoirs and Community Springs—The Coulee Utilized to Form Water Supply—Saskatchewan Dry in Southwest, Wet in Northeast.
I am very much pleased at this particular time to give an account of a few of my observations while acting as an inspector of water supplies in the province of Saskatchewan, for the Irrigation Branch of the Department of the Interior, during the field seasons of 1916 and 1917 and the part of 1918 just past. My chosen subject of “Rural Community Water Supplies” is in itself a very wide subject, inasmuch as it is only in its infancy of development. Nothing in my travels caused more wonderment in my mind than to drive into a farmyard in quest of a refreshing drink of water on a hot day and to find that the only available drink was warm rain water, or stale lemonade, backed up with the excuse that the children had not yet gone to town for the water. I wondered what kind of people they were who could endure a life of this kind. The growing of wheat is the solution, and, strange to say, this extremely dry belt holds one of the best records for wheat production.
Wet Northeast, Dry Southwest
Owing to the fact that my inspections have been confined to the province of Saskatchewan, I will of necessity confine my remarks to it, and ask you to picture the map in your mind’s eye. Generally speaking, it is known as wet in the north and dry in the south, but in reality it is wet in the northeast half and dry in the southwest half, the division being the line of tree or brush growth. This line commences in the northwest at about Lloydminster, and follows down the North Saskatchewan River to a point about half-way between Saskatoon and Prince Alberta, thence in a southeasterly direction to the southeast corner of the province. The growth in the wet area starts with small poplar and willow, and gradually grows into the larger type as one proceeds north, until township 55 is reached, where timber of spruce and hemlock is obtained fit for saw-mill purposes. Over this territory, surface water as well as ground water is found in abundance and nearly all the streams are perennial.
The southwestern part of the province, known as the dry part, is mostly open prairie, and surface water is very scarce in the summer and fall of the year. The old creek beds and sloughs become dry so that underground water has to be found, or else surface water impounded and held for dry seasons. Groundwater is not, as a general rule, hard to find, although there are isolated districts which are most difficult and expensive to prospect. In these districts the average farmer is not financially able to procure it by deep-well drilling, and 1 know of cases where drilling up to 1,500 feet has failed to locate water. In these districts the government has assisted the farmers by creating reservoirs of various types, for the purpose of holding the spring runoff, as well as any precipitation which might occur during the summer.
Water Supplies Primitive
Generally speaking, small towns and villages are in a primitive state as regards their water supplies. In some cases water is hauled from neighboring springs and sold to the residents in pails or by the barrel. This, however, is due to the lack of funds which might better the conditions. In other cases the town pump is in evidence at the principal street corner. The larger towns have their own system, which is a subject in itself.
*Excerpts from a paper read before the Second General Professional Meeting of the Engineering Institute of Canada, held at Saskatoon, Sask., August 8th-10th, 1918.
Through the information furnished by the hydrometric service covering the larger streams, and the inspections and reports on the various schemes in the drainage basins, water administration can be handled in a form of bookkeeping, and in this way the department has an intelligent check on the water supply of the territory, over which the act has jurisdiction.
The Spring Most Sought After
The spring is, of course, the most sought-after source of water supply in these dry districts, being perennial by nature, and because of the purity of the supply. There
is, however, a wide diversity of opinion as to the limits of the jurisdiction of the Irrigation Act in comparison with the development which might bring the scheme under the beading of a “well.”
The difference, in my opinion, is simply this: Where a man of his own ingenuity finds water by digging into the surface soil, the water found by him is his own property, to do with as he may see fit. If, however, he finds a surface indication of water, if only in the form of a miniature marsh, and by developing this indication by any means whatsoever, he produces a constant supply which of itself remains constantly at the surface or near
it, this supply is a spring water supply and the right to it is vested in the Crown. The Crown, of course, reserves to the land owner the first rights to the supply, and the balance, if any, is licensed to the applicant.
The development of springs depends largely upon conditions, but for rural communities the general rules are as follows: First, to establish a graded road to and from the site, next to construct a box to which a pumping appliance can be installed, and next, the excavation of a reservoir for the use of stock. Sketch No. 1 attached shows the general layout for development for community springs.
Community and Other Reservoirs
This is, indeed, the most interesting type of water supply development from an engineering standpoint, inasmuch as the construction of the dam requires considerable engineering judgment, especially in view of the fact that stone and concrete are not always available in these dry districts. The best and most efficient reservoirs which have come under my observation is the combined reservoir and dugout in narrow coulees, say, up to a depth of about 50 feet, where the supply is more readily replenished from the larger drainage basin or watershed and the reservoir is protected from hot winds, etc. They are less susceptible to flooding, and depth of water is obtained by means of a dugout. The dam is usually low, and the spillway problem is therefore more readily solved. The spillway capacity is invariably under-estimated; that is, they are built foV normal conditions rather than extreme flood conditions. Community dams are usually built on road allowances, the top being used as roadways. This has been disputed as “good practice,” but I am personally in favor of it, especially on account of having the water convenient to the highway, and the tact that the work is not duplicated.
How to Construct a Dam
A brief form of instructions for the construction of a dam aside from the general specifications as to dimensions and slopes might be cited as follows:—
On commencing the construction of a dam it is important that the site be entirely stripped of all sod and vegetable matter, and that same be removed to a convenient point, to be used after to sod down the top and lower slope, on completion of the work. The ground thus stripped should have furrows ploughed every four or five feet, at right angles to the coulee, in order to give a rough surface to the ground to resist seepage. The puddled wall trench should then be dug to a depth well below the top soil or loam, into an impervious strata and the trench rebackfilled with a selected clay, and well puddled with water. When this trench is filled the main portion of the dam should be commenced, and the material used should be a suitable clay, free of vegetable matter and stones. The borrow pits which should be located on each side of the dam on the upper side, should therefore be stripped of both sod and top soil. The masolidated by tamping, but special runways should be terial should be spread on in thin layers, and well conavoided. It is also important that the sides be carried up considerably faster than the centre, and that the centre immediately over the puddle wall be continued up into the embankment for at least 3 1/2 feet.
On completion of the earthwork, a cobble-stone riprap should be placed on the entire upper slope, to assist the clay to maintain its slope as well as to prevent wave wash from wind. If cobble-stones are not available, lumber is sometimes used for this purpose, in the form of an ordinary board fence constructed in the slope. Shrubs are often planted from the water line to the top on the upper and on the entire lower slope. The balance of the earth work should then be seeded down, after the available sods from stripping have been placed.
The spillway must take care of the entire runoff after the dam has been filled, and in no case is any water to be permitted to go over the top of the dam. Providing the owner can afford this expense, the spillway should be paved with concrete or hand-placed rip-rap for a distance of about 20 feet on each side of the centre line of the dam, and the paved portion should be level so that the current in it will be reduced as much as possible. After leaving this portion, care should be taken to ditch the waterway from the embankment, and the ditch should be well riprapped to prevent erosion.
After completion, the embankment should be inspected from time to time, and any defects, such as settlements, rain wash, wear from stock tramping, or damage from burrowing animals, should be repaired. Special attention should be paid to the spillway after the spring run-off to see that the rip-rapping is not undermined or washed out.
Reservoirs of the type outlined above with the spillways at or above the high-water line are, of course, difficult to clean, but they are built nowadays in this manner as a matter of economy. Sluice pipes equipped with valves, or concrete spillways, equipped with stop logs or gates would, of course, make them more complete.
In some private schemes I have found some very unique forms of construction, especially where people from foreign lands have constructed the dams. One form is to build a rustic fence of poles, interlaced in a strong manner, and then covered with earthwork, having the fence sticking up through the upper slope at the highwater line. Sometimes this fence is seen on the lower slope, and where this type is used the dams are usually intact, while others nearby have been washed out of existence. Sketch No. 2 shows a general layout for community reservoirs in coulees.
Dugouts Another Form of Storage
The most peculiar form of reservoir is the dugout located on the flat open prairie in heavy gumbo soil. These dugouts are generally about 200 feet long by 50 feet wide and from 10 to 15 feet deep, with sloping sides, holding about 700,000 gallons of water. They are equipped with pumping appliances for the taking of water, and fenced with high board fences to protect them from pollution. They are rather popular, as the water does not deteriorate very rapidly, on account of the depth and the minimum surface area. Plant life is also kept down, and the cost of construction and maintenance is comparatively low. Dugouts are sometimes located in dry slough beds, on account of the impervious soil and because of the natural location for replenishment. But this is not a desirable location, because of the quality of water in them. It is usually high in color from decayed vegetation, and therefore more infested with insects.
A dugout of this kind will serve an area of about nine square miles, based on the following estimate. The average farm in the grain district is about one-half section or 320 acres of land, each farmer supporting about six persons, ten horses, ten cows, and ten hogs, which will consume about 600 gallons of water per diem, or a little less. So that the estimated water supply for each township would be about 43,000 gallons per day, at all times, or about 72,000 gallons per day in the threshing season, considering that only about one-quarter of the farmers of the township are actually threshing at the same time. The standard dugout of about 700,000 gallons capacity, with four to each township, in addition to the usual private means of water supply, will give a full 40 days supply, which is generally the length of the brisk threshing iseason for which these 40 days are considered. Sketch No. 3 shows the general layout for community dugouts on flat open prairie.
Losses from Open Reservoirs
Just here I might add a few remarks concerning the estimated water losses from open reservoirs. There are two noticeable agents of losses. First, evaporation, and second, percolation. The first means evaporation into the air due to atmospheric conditions, and degree of shade from the mid-day sun and hot winds. The second means that portion taken up by seepage into the ground, plus that portion taken up by plant life. Generally speaking, open reservoirs lose about forty inches per year from these agents, depending largely on the protection as well as the depth. It is advisable to locate the reservoir with these points in view, viz., a minimum surface area with a maximum depth.
It is my opinion that the problem of water supply is going to become more acute as the country becomes more settled, and the question is going to require more engineering aid than it has in the past, if the best results are to be obtained.
Signs of insufficient investigations are noticeable at times, such as dry reservoirs, indicating unsuitable soil conditions, and let us hope that the practice of installing incomplete schemes, because of lack of money, or other excuses, will be stopped, if for no other reason than that these dilapidated schemes are bad examples in the country. It is false economy to half build a big scheme. Better to build two small schemes well. This is another case where the Public Utilities Commissions of the provinces could increase their efficiency by making better use of the engineering profession.