| Streams. | I.—July volume, in feet per second. | II.—September volume, in feet per second. | III.—Ratio of I to II. |
|---|---|---|---|
| City Creek | 119 | 32 | 3.7 |
| Emigration Creek | 24 | 8 | 3.0 |
| Parley’s Creek | 72 | 29 | 2.5 |
The comparison is not decisive, but it seems to show that the problem demands for its solution a careful examination at the “critical season.” If the Ogden and Weber had been measured in September, as were the other streams, their volumes would probably have been found less than in October; and this consideration appears to throw the balance of evidence against the competence of the rivers to water the contiguous lands.
But if their incompetence shall be proved, it does not follow that the lands must go dry. The Bear at the north and the Jordan at the south have each a great volume of surplus water, and either supply can be led without serious engineering difficulty to the lower levels of the delta of the Weber.
In the following table are summed the agricultural resources of the Weber drainage basin:
| Tracts. | Square miles— | |
|---|---|---|
| Cultivated in 1877. | Cultivable. | |
| Kamas Prairie (northern edge) | .7 | 3.0 |
| Peoa to Hennefer, inclusive | 8.5 | 9.0 |
| Parley’s Park | 3.2 | 3.2 |
| Uptown | .5 | 2.0 |
| Echo Creek | .3 | .9 |
| Croydon | .4 | .5 |
| Round Valley | .5 | .5 |
| Morgan Valley | 6.0 | 6.9 |
| Ogden Valley | 4.1 | 8.0 |
| Delta Plain | 91.0 | 219.0 |
| Total | 115.2 | 253.0 |
The estimate of 219 miles of cultivable land on the Delta Plain includes 15 miles that will probably never be irrigated, but may nevertheless be farmed.
The total area of the Weber basin (including the whole plain from Bonneville to Centerville, and excluding the main body of Kamas Prairie) is 2,450 square miles; 4³⁄₄ per cent. of the area is now under cultivation, and 10¹⁄₃ per cent. is susceptible of cultivation.
The Jordan River is the outlet of Utah Lake, and runs northward, entering Great Salt Lake at its southeastern angle. On the right it receives a number of large tributaries from the Wasatch Range. The largest tributary of Utah Lake is the Provo River, which rises in the Uinta Mountains close to the heads of the Weber and Bear.
From the mouth of its mountain cañon the Provo enters Kamas Prairie, and it hugs the south margin of the plain just as the Weber hugs the north margin, passing out by a narrow defile at the southwest corner. At one time in the history of the prairie the Provo flowed northward through it and joined itself to the Weber. The surface of the prairie was then lower than now, and the sand and gravel which the river brought from the mountains accumulated upon it. Eventually the Provo built its alluvium so high that its water found a new passage over the wall of the valley. The new channel, affording a more rapid descent than the old, quickened the current through the valley, and caused it to reverse its action and begin the excavation of the material it had deposited. So long as the river built up its bed, its channel was inconstant, shifting from place to place over the whole plain; but so soon as it began to cut away the bed, its position became fixed and the plain was abandoned. The river now flows in a narrow valley of its own making, 150 feet below the surface of the plain. As a result of this mode of origin, Kamas Prairie slopes uniformly from the Provo to the Weber, and it would be an immense undertaking to irrigate it with the water of the Weber. But the Provo River can be returned to its ancient duty with comparative ease. A few miles of canal will suffice to carry its water to the upper edge of the plain, and thence it can be led to every part. Already a small canal has been constructed and its enlargement may convert the whole prairie into a meadow. Thus the prairie, although part of the drainage basin of the Weber, belongs to the irrigation district of the Provo.