delivered the opinion of the court.
The court of appeals, in passing upon the questions presented by the record in this case, held that a reservoir company taking water for storage, from a tributary, is not liable to be enjoined from so doing at the suit of an appropriator of water from the main stream above the mouth of the tributary,, for the reason that the diversion by the former could not injure the latter; and also held, that the right of appropriators below the point where such tributary joins the main stream cannot be determined except in a proceeding to which they are parties; and stated in the opinion, that it did not appear from the record there were any appropriations senior to those of the storage company below the mouth of Dry creek, and for these reasons reversed the judgment of the district court. The Larimer and Weld Reservoir Co. et al. v. The Water *91Supply and Storage Co., 7 Colo. App. 225. These were the only questions passed upon by the court of appeals, and it becomes necessary to first determine whether or not its judgment was correct.
In brief, it appears from the pleadings, stipulation regarding the facts, and the findings of the trial court, which are supported by the evidence, that the ditch of the storage company takes its water from the Cache la Poudre river; that the reservoir company diverts its water from Dry creek; that this stream joins the main stream below the intake of the storage company’s ditch; that the appropriation of the storage company is senior to that of the reservoir company; that there are appropriations below the point where Dry creek joins the river senior to both the reservoir and storage companies; that in times of scarcity of water there is not sufficient flowing to the head-gate of the storage company’s ditch to supply it and the senior priorities below the mouth of Dry creek; that the water commissioner permits the reservoir company to divert the waters of Dry creek into its reservoir, and that the latter company claims the right so to do, without regard to the rights of the storage company.
The question here presented is identical with that passed upon in the case of The Platte Valley Irrigation Company v. The Buckers Irrigation, Milling and Improvement Company, ante, p. 77, namely, an appropriator from a stream may require a junior from a tributary thereof which joins such stream below the intake of the former’s ditch, to surrender the use of water from the tributary in favor of appropriations from the main stream senior to both below the point where the tributary joins it, to the extent that the volume flowing to the head-gate of such appropriator is insufficient to supply such senior appropriations and his own; or, in other words, bearing in mind the conditions here present, an appropriator from a stream may require a junior from a tributary which joins such stream below the point of the intake of the former’s ditch, to surrender his use of water in favor of appropri*92•ations from the main stream senior to each below the point where the tributary joins such stream, before he does.
In this case the facts established clearly bring it within the ■doctrine above announced. The storage company diverts its water from the main stream; the reservoir company from Dry creek. There are appropriations senior to both below the point where Dry creek joins the stream. The appropriation of the storage company is senior to that of the reservoir company. In times of scarcity of water in the main ¡stream, there is insufficient flowing to the head-gate of the ¡storage company to supply it and the senior appropriations below, and, therefore, when these conditions exist, the storage company has the right to demand that the reservoir ■company shall first surrender the water which it claims the right to divert from Dry creek, in favor of senior appropriations below the mouth thereof, on the main stream, thereby, to this extent, augmenting the flow which shall reach such ¡senior appropriations, and correspondingly decreasing the volume which must pass by the head-gate of the storage company for the use of such appropriations. It was held by the ■court of appeals, that the right of appropriators below the point where Dry creek joined the main stream, could not be determined except in a proceeding to which they were parties, but that was not a question presented for determination in this action. The parties conceded there were appropriators prior to both below the point where Dry creek joined the river, and the question for the court to determine was, not the rights of such appropriators as against either of the parties to this action, but what were the rights betw.een the litigants with reference to the question as to which should first ¡surrender water, in order to supply such senior priorities. •Our conclusion is, that the court of appeals erred in its application of the law to the facts as presented by the record; .¡and, not having passed upon the other assignments of error ■of the reservoir company, it becomes necessary to dispose ■of them in this court. The complaint of the storage company was inartificially drawn, certainly ambiguous; and, *93alone, may have failed to state a cause of action, because it did not appear therefrom that the diversion of the Reservoir-company from Dry creek was in any manner injuriously affecting its rights. A defective complaint, however, may be aided, and omissions supplied, by the answer, D. & R. G. Ry. Co. v. Cahill, 8 Colo. App. 158, or an allegation in the-replication, if acquiesced in. Ibid. The reservoir company, by its answer, made it clear that Dry creek joined the river-below the intake of the Larimer county ditch, and the storage company, by its replication, though in an informal manner, averred it was being required to surrender water for the use of senior appropriators below the mouth of Dry creek in volume equal to that diverted from this source by the reservoir company, to which statement in the replication the latter interposed no objection. Neither of these statements, appeared in the complaint when the demurrer was interposed, and conceding that their omission was fatal, the judgment of the court, in overruling the demurrer, was error without prejudice; for, with these omissions subsequently supplied, a cause of action was stated in favor of the storage company.
It appears, from the facts as stipulated by counsel at the trial, that land of the consumers under the ditch of the-storage company had been irrigated by water diverted through this channel before the construction of the reservoir by the reservoir company. This conclusively settled that the-appropriation of the Larimer county ditch antedated that, of the reservoir company from Dry creek, and, therefore, the admission of the decrees, awarding the Larimer county ditch a priority to the use of water from the Cache la. Poudre river could in no manner have affected the finding-of the trial court, with reference to the relative priorities of the litigants; and it is, therefore, unnecessary to determine-whether such decrees were material or immaterial in this case.
The judgment which the reservoir company pleaded as a. second defense in this action was res adjudicate/, between the parties to this suit on the one question as to which had the* superior right to utilize the waters of Dry creek by direct. *94diversion; bnt this is not the question which the parties are here litigating, nor could it, under the issues made by the pleadings in that case, have been litigated or adjudicated therein, and, therefore, this plea was no defense to the action instituted by the storage company, for a former judgment on the merits is only conclusive between the parties when the question to be determined in the second action is the same question judicially settled in the first, Huntley v. Holt, 29 Conn. 102; but such judgment does not operate as an estoppel with respect to matters not determined therein which could not have been properly litigated under the issues in the action in which the judgment was rendered, see note to above case, 21 Am. St. Rep. 74.
It appears that the water from Dry creek ditch, which wasted into Dry creek, was water diverted from the river. Waste waters which are again returned either to the main stream, or its tributaries, become a part of the waters of the stream the same as though never diverted, and inure to the benefit of appropriators in the order of their appropriations ; and the appropriation by the storage company, being senior to that of the reservoir company, the latter cannot complain of the order of the trial court, requiring it to desist from diverting the waste water from Dry creek ditch, when the storage company is in a position to demand that the reservoir company surrender its rights to the waters of Dry creek in favor of appropriations below the point where this creek joins the main stream. Kinney on Irrigation, §§183, 259.
The judgment of the district court should be affirmed; and the judgment of the court of appeals is, therefore, reversed, and the cause remanded, with directions to affirm the judgment of the trial court.
Reversed and remanded.