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Water Quality

Water quality in the Pembina River below Walhalla during low flow conditions is extremely poor. At times, the dissolved oxygen content has been zero and the biochemcial oxygen demand as high as 15 parts per million. A supplemental flow is needed to dilute waste effluents and compensate for channel losses in this reach of the river.

Assuming that the wastes from each of the communities and industries concerned will receive adequate treatment prior to being discharged to the River, it is estimated that the supplemental flow required will increase from 2 cfs at present to 3 cfs by the year 2010. This supplemental flow for quality control cannot be assured under existing conditions.

Moisture Deficiency

Agricultural risks associated with marginal and variable rainfall have strongly influenced the selection of crops, farm practices, and the economy of the area. The success of agriculture and its related industries is primarily dependent on the adequacy and timely occurrence of rainfall during the growing season. Moisture required for full crop production is approximately 20 inches a year, if ideally distributed. Precipitation during the growing season seldom exceeds 13 inches. During the past 42 years the annual moisture requirements to supplement rainfall have varied from 6 to 14 inches, and during six years of drought exceeded 12 inches a year.

The soils near the base of the Escarpment between Walhalla and Winkler are generally deep and fertile. They are free from harmful concentrations of salts and sodium and have adequate water holding capacity. The topography is excellent. The barrier to ground water movement is the dense lake clays, found from 6 to more than 30 feet below the ground surface in the arable lands. The relatively shallow depth to the underlying clay barrier in the southern portion imposes a drainage problem.

The economy of the area, which is almost entirely maintained by agriculture, suffers from the inadequacy of moisture supplies during the growing

season.

Recreation

Adequate water related recreational facilities such as boating, water skiing, fishing, picnic and camping areas are lacking in much of the Pembina River Basin. Recreational use has been confined to Rock and Pelican Lakes. They are shallow and subject to fluctuation of levels and in consequence boating activities are limited. Bone, Overend and Swan Lakes are extremely shallow and have a slough-like appearance. Heavy algae growths have occurred in all Pembina Valley Lakes in Canada. Toxic algae were prevalent in Pelican and Rock Lakes in the summer of 1962. Residents of the northeastern part of North Dakota must travel considerable distances to recreational areas because few natural lakes exist in that part of the State.

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Game fish production is marginal in Pelican and Rock Lakes despite good water quality and an apparently adequate food supply. The other lakes are incapable of supporting a year-round fish population. Lakes in this region with less than 10 feet of water regularly undergo severe winter kills in which nearly all fish are lost. Even lakes with depths ranging from 10 to 20 feet have heavy losses in 10% to 50% of the winters.

Fishing in the lower portion of the Pembina River is restricted to the period of spring high water when fish move upstream from the Red River. Present conditions are not conducive to the support of game fish of good quality.

Present Use

The water resources of the Pembina River Basin have been developed only to a modest extent. Current use is limited to supplying water for the communities of Altona, Gretna, Neche and Pembina, of which the combined population in 1960 was 3,800. The total capacity of their water treatment plants is 900,000 US gallons per day.

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The River and its tributaries receive wastes from nine communities, all of which either treat or have plans for treatment of waste water.

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SECTION V

THE BOARD'S INVESTIGATION

The Board's comprehensive investigation included topographic, soil and geological surveys; collection and analysis of hydrological and economic data; hydraulic studies, preliminary designs and cost estimates; evaluation of potential benefits; and project formulation studies. All segments of the field and office studies proceeded simultaneously. During the conduct of the investigation the Board, its engineering committee and representatives of the participating governmental agencies in both countries held numerous meetings to coordinate studies and procedures so the results obtained would be comparable. Details are in the Board's report and its twelve appendices.

Field Surveys

Foundation drilling and seismic refraction surveys were undertaken at three dam sites. Laboratory tests were run on the soil samples taken to determine the stability of the embankment, foundation conditions, the design of the earthfill dams, the location of the spillways, conduits and sources of construction materials.

Topographic maps with a scale of 1:4800 and a contour interval of 10 feet were prepared from aerial photographs covering the Pembina River Basin. In addition, detailed topographic maps with one foot contours and a scale of 1:4800 in North Dakota and 1:2400 in Manitoba were prepared for the potential irrigable areas.

A detailed land classification was made to determine the extent, nature and class of land suitable for irrigation. The potential irrigable area was classified according to soil, topographic and drainage characteristics. The soil survey and land classification covered 38,000 acres in Manitoba and 26,000 acres in North Dakota.

Water samples taken from five stations were analysed to determine if the waters of the Pembina River were suitable for sustained irrigation without special practices and if they would meet the standards for drinking water. Measurements were also made to determine the suspended sediment and bed load material carried by the Pembina River. These data were used to calculate the sediment storage requirements.

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