1, 2. The grounds of attack upon the constitutionality of the act are set forth in the petition. Some of them are not urged in the brief of counsel for the plaintiffs in error. Under the practice in this court, these will be treated as abandoned. Others do not point out what provision of the constitution is violated. These will not be considered. Morton v. Nelms, 118 Ga. 786 (45 S. E. 616).
3. The act authorizes the establishment of drainage districts throughout the State, under certain circumstances, and provides for the appointment of commissioners who are clothed with authority to carry into effect the provisions of the act. Among the powers conferred was the power to levy assessments against property to be benefited by the drainage, for its pro rata amount of the cost of the improvement. Assessments of this character are radically different from ad valorem taxes, and are not taxes within the meaning of the constitution. Hayden v. Atlanta, 70 Ga. 817; Speer v. Athens, 85 Ga. 49 (11 S. E. 802, 9 L. R. A. 402); City of Atlanta v. First Presbyterian Church, 86 Ga. 730 (13 S. E. 252, 12 L. R. A. 852); Georgia Railroad Co. v. Decatur, 137 Ga. 537 (73 S. E. 830, 40 L. R. A. (N. S.) 935).
It is said that the act is unconstitutional, for the following, among other reasons: (a) It “is in conflict with the constitution *717of the State, which provides 'that the taxation shall be uniform, because it is not the levy of a tax by a county, nor any municipal corporation in a county, or within any political division recognized or pointed out by the constitution of the State.” (&) It is in violation of article 4, section 1, paragraph 1, of the constitution, which declares: “The right of taxation is a sovereign right, inalienable, indestructible, is the life of the State, and rightfully belongs to the people in all republican governments, and neither the General Assembly, nor any nor all other departments of government established by this Constitution, shall ever have the authority to irrevocably give, grant, limit, or restrain this right; and all laws, grants, contracts, and all other acts whatsoever, by said government or any department thereof, to effect any of these purposes, shall be and are hereby declared to be null and void for every purpose whatsoever; and said right of taxation shall always be under the complete control of, and revocable by, the State, notwithstanding any gift, grant, or contract whatsoever by the General Assembly.” (c) It “is unconstitutional,” because the constitution “only permits the levying and collecting by counties of a tax for ‘necessary sanitation/ whereas section three of the act authorizes the assessing of the property, levying and collecting a tax or assessment, for the benefit of the public health, or any public highway, or be conducive to the general welfare of the community, whether the improvements proposed will benefit the lands sought to be benefited; all save the public health being without the purview of sanitary legislation, and without the authority to tax granted to counties by the constitution.”
It will be perceived' that all of these grounds of attack depend on the assumption that the act authorizes the levy of a tax within the meaning of the constitution. As the act does not authorize the levy of such a tax, it follows, without the necessity of considering other reasons urged for and against the validity of the act, that it is not subject to any of the foregoing objections.
4. It is also said that" the act falls under no provision of the constitution authorizing the levy of an assessment upon private property' without the consent of the landowner, and that it is in violation of article 1, section 1, paragraph 2, of the constitution, which declares: “Protection to person and property is the paramount duty of government, and shall be impartial and complete.” Civil Code, § 6358. The validity of the enactment rests in the *718police power of the State. By reference to section two of the act, it appears that the law is not intended to apply unless, among other things, "public benefit, or utility, or the public health, convenience, or- welfare will be promoted by draining, ditching, or leveeing” the land. It thus appears that the act is founded on the principle of public benefit. Sanderlin v. Luken, 152 N. C. 738 (68 S. E. 225). There are decisions dealing with drainage, and with its kindred subject irrigation, which hold, in effect, that, in determining whether the improvement contemplated by the statutes is for private or public benefit, it is not absolutely necessary that the public at large should be benefited. 2 Kinney on Irrigation and Watercourses, § 1068, and citations; Lewis v. Gordon, 20 Wash. 805 (54 Pac. 779); Coster v. Tidewater Co., 18 N. J. Eq. 54; O’Reilly v. Kankakee Valley Drainage Co., 32 Ind. 169. If the use and benefit be common to all who are assessed, and not for particular individuals, it will be sufficient. 1 Lewis on Eminent Domain (3d ed.), § 254, and citations. These and other authorities recognize that drainage, such as is contemplated by the statute under consideration, may amount to a public benefit. Statutes oE the character just referred to, for promotion of the public welfare, have been recognized as a valid exercise of the police power of the State. In Re Hegne-Hendrum Ditch No. 1, 80 Minn. 58 (82 N. W. 1094); Mound City Land Co. v. Miller, 170 Mo. 240 (70 S. W. 721, 60 L. R. A. 190, and notes, 94 Am. St. R. 727); Donnelly v. Decker, 58 Wis. 461 (17 N. W. 389, 46 Am. R. 637); Fallbrook Irr. District v. Bradley, 164 U. S. 112 (17 Sup. Ct. 56, 41 L. ed. 369); 10 Am. & Eng. Enc. Law, 222; Hagar v. Reclamation District No. 108, 111 U. S. 701 (4 Sup. Ct. 663, 28 L. ed. 569). In the case last cited it was held: "It is within'the discretion of the legislature of California to prescribe a system for reclaiming swamp lands, when essential to the health and prosperity of the community, and to lay the burden of doing it upon the districts and persons benefited.” We think the act under consideration was a valid exercise of the police power of the State.
5. Another attack upon the act was on the ground that it was in conflict with article 7, section 7, paragraphs 1 and 2, of the constitution (Civil Code, §§ 6563, 6564), which provide: "The debt hereafter incurred by any county, municipal corporation, or political division of this State, except as in this constitution provided *719for, shall not exceed seven per centum of the assessed value of all the taxable property therein, and no such county, municipality, or division shall incur any new debt, except for a temporary loan or loans to supply casual deficiencies of revenue, not to exceed one fifth of one per centum of the assessed value of -taxable property therein, without the consent of two thirds of the qualified voters thereof at an election for that purpose, to be held as may be prescribed by law; but any city, the debt of which does not exceed seven per centum of the assessed value of the taxable property at the time of the adoption of this constitution, may be authorized by law to increase, at any time, the amount of said debt, three per centum upon such assessed value.” “Any county, municipal corporation, or political division of this State, which shall incur any bonded indebtedness under the provisions of this Constitution, shall, at or before the time of so doing, provide for the assessment and collection of an annual tax, sufficient in amount to pay the principal and interest of said debt within thirty years from the date of the incurring of said indebtedness.” Under this ground of attack it is insisted that the statute amounted to an unauthorized attempt to empower the commissioners to issue bonds, which, in effect, without the sanction of two thirds of the voters at an election duly held, amounted to the creation of a debt. Under the terms of the drainage act, the bonds which it is provided the drainage commissioners may issue are not a general liability upon the drainage district or payable out of any general funds it may have; but they are payable solely out of assessments previously made upon property benefited by the local improvement, as provided by the act. In other words, the assessment is made upon property for a local improvement. The owners of the property have the privilege of paying the assessments within a specified time; and for the balance unpaid at that time, what are called bonds may be issued by the commissioners. But, taking the act as a whoU, tbjse bonds are only payable from the collection of the unpaid assessments; and if there is a default for a certain time in the payment of the bonds, provision is made for compelling the officers to collect such assessments so as to pay the amount of installments due. It has been held by a number of authorities that such a bond or certificate, so payable, does not constitute an indebtedness against the political division, vrithin the meaning of clauses of State constitutions quite similar *720to our own. It has sometimes been suggested that the issuance of such bonds amounted to a quasi assignment of the assessment or its proceeds to the extent necessary for payment. Sometimes what is called the special-fund doctrine has been invoked, — a doctrine, however, which one or two courts have carried so far as practically to render ineffectual the constitutional limitation. It might be suggested that, under the terms of the act before us, the drainage commissioners do not possess property derived from various sources, or levy general taxes, but stand in a peculiar relation to the bondholder, which might be analogized to that of agents in the collection of the assessments and payment of the bonds from only the one source from which they are payable.
In view of the terms of the act-and the construction we have given to it, we are.of the opinion that it does not violate the clause of the constitution which prohibits municipal corporations, counties, or political divisions of the State from incurring an indebtedness without an election first being held therefor. Gray on Limitations of Taxing Power, §§ 2101-2109, and citations; 2 Dillon on Municipal Corporations (5th ed.), §§ 893, 827; Sanderlin v. Luken, supra; Elliott v. McCrea, 23 Idaho, 524 (130 Pac. 735).
The case differs from the class of cases in which a municipality assumes a general and primary liability to pay the cost of the improvement, among which cases are Sanders v. Gainesville, 141 Ga. 441 (81 S. E. 215); Martin v. Tyler, 4 N. D. 278 (60 N. W. 392, 25 L. R. A. 838); McAleer v. Seattle, 2 Wash. 653 (27 Pac. 557); City of Ottumwa v. City Water Supply Co., 119 Fed. 315 (59 L. R. A. 604, 56 C. C. A. 219).
6. Having held that the grounds of attack upon the constitutionality of the act are not meritorious, it is unnecessary to deal with the question of estoppel, which was submitted to the trial judge for decision. The statute being authority for the collection of the assessments which it was sought to enjoin, it was not erroneous for the judge to refuse to grant the interlocutory injunction.
Judgment affirmed.
All the Justices concur.