PER CURIAM.

Plaintiff appeals as of right the judgment of the trial court in favor of defendants denying the relief requested in plaintiff's complaint.

Plaintiff leased two lots of an industrial complex to a corporation controlled by the defendants on November 12, 1968. Plaintiff subsequently became the owner of a small area of property at the southern end of the two lots, and this property also became a part of the defendants' leasehold. In 1969, this new area was developed, a lawn established, and a ditch put in. This ditch carries water off other land owned by plaintiff and is the subject of the instant case. Testimony differed as to when it was first developed; plaintiff testified that the work done in 1969 was a modification of a ditch that had existed prior to the acquisition of the property to the south of the original two lots, although he had previously given answers to written interrogatories stating that the ditch was first put in simultaneously with the other improvements. Defendant Frank Eger testified that the ditch did not exist prior to the establishment of the leasehold, but that it was constructed after he commenced occupation.

A history of litigation between the parties commenced in 1972 when defendants' corporation brought suit seeking specific performance of an option to purchase the property that was contained in the lease. A consent judgment was entered and defendants took title to the property. On October 9, 1973, defendants announced to plaintiff their intention to grade and level that portion of the property that contained the ditch, a manhole, access structures, and buried drain tile. Plaintiff filed suit seeking an injunction against the defendants prohibiting them from interfering with the drainage ditch. Accelerated judgment was granted to defendants, but this Court reversed and remanded for trial. Schmidt v Eger, 69 Mich. App. 457; 245 N.W.2d 90 (1976), lv den 399 Mich. 867 (1977). At trial, plaintiff relied on three theories in support of his claim for an injunction. Judgment was for defendants and plaintiff has appealed as of right, raising claims of error in the trial court's application of each of his three theories.

I.

Plaintiff claims the drainage ditch represents an easement by implied reservation. To establish an implied easement, three things must be shown: (1) that during the unity of title an apparently permanent and obvious servitude was imposed on one part of an estate in favor of another, (2) continuity, and (3) that the easement is reasonably necessary for the fair enjoyment of the property it benefits. Harrison v Heald, 360 Mich. 203; 103 N.W.2d 348 (1960), Rannels v Marx, 357 Mich. 453; 98 N.W.2d 583 (1959), Koller v Jorgensen, 76 Mich. App. 623, 628; 257 N.W.2d 192 (1977), lv den 402 Mich. 843 (1977). The party asserting the easement has the burden of proving the claim by a preponderance of the evidence. Kahn-Reiss, Inc v Detroit Northern Savings Loan Ass'n, 59 Mich. App. 1, 12; 228 N.W.2d 816 (1975). The trial court found that the continuity element was established, given the nature of drains, and we agree. Waubun Beach Ass'n v Wilson, 274 Mich. 598, 606; 265 N.W. 474 (1936), Bubser v Ranguette, 269 Mich. 388, 392-393; 257 N.W. 845 (1934), 2 Thompson on Real Property, § 354, p 344. Our discussion is limited to the remaining two elements.

A. Necessity

On the necessity element, the trial court held that plaintiff needed to establish that the easement was strictly necessary before it would be implied. We hold that this was error, and that plaintiff needed only to establish that the easement was reasonably necessary. We do note, however, that some confusion in this regard is justified, as Michigan law has been less than clear on the point and as easements by implication may arise under different circumstances.

An implied easement may arise in essentially two ways. First, it can be implied from necessity. In this situation, an estate has been severed, leaving the dominant estate without a means of access. Before an easement will be implied in this situation, the party who would assert the easement must establish that it is strictly necessary for the enjoyment of the property. Mere convenience, or even reasonable necessity, will not be sufficient if there are alternative routes, even if these alternatives prove more difficult or more expensive. All implied easements are based on the presumed intent of the parties, but this sort is additionally supported by the public policy favoring the productive and beneficial enjoyment of property. Easements implied from necessity have been recognized in Michigan as requiring a showing of strict necessity. Waubun Beach Ass'n v Wilson, supra, Goodman v Brenner, 219 Mich. 55; 188 N.W. 377 (1922), Moore v White, 159 Mich. 460; 124 N.W. 62 (1909), Birch Forest Club v Rose, 23 Mich. App. 492; 179 N.W.2d 39 (1970). This sort of implied easement is not dependent on the existence of any established route or quasi-easement prior to the severance of the estate by the common grantor; it is first established after the severance.

The easement with which we are involved in the instant case is of a different type, what Dean Cribbet refers to as easements implied from quasi-easements. It requires that at the severance of an estate an obvious and apparently permanent servitude already exists over one part of the estate and in favor of the other. It also requires a showing of necessity, but whether that necessity needs to be "strict", or only "reasonable", traditionally has depended on whether the easement claimed was an implied grant, or an implied reservation. Aigler, Comment: Real Property — Easements by Implication — Creation of Easements by Implied Reservations in Michigan, 59 Mich L Rev 432 (1961).

It appears to be the position of a majority of jurisdictions that an implied grant of an easement requires only a showing of reasonable necessity, while an implied reservation of an easement in the grantor requires a showing of strict necessity. The difference seems based on the idea that a grantor will not be allowed to derogate from the grant by alleging to retain interests which the deed purports to convey. Because the grantor is not allowed to assert the reservation of an implied easement based on the existence of a pre-existing servitude or quasi-easement, the claim of an implied reservation must, under this view, proceed as if no servitude or quasi-easement existed, and requires a showing of strict necessity as in the case of an easement implied from necessity.

Several Michigan cases have adopted this position, and held that when an implied reservation is involved, as in the instant case, a showing of strict necessity is required. Brown v Fuller, 165 Mich. 162; 130 N.W. 621 (1911), Bubser v Ranguette, supra, von Meding v Strahl, 319 Mich. 598, 605-606; 30 N.W.2d 363 (1948), Kahn-Reiss, Inc v Detroit Northern Savings Loan Ass'n, supra, Wilson v Anglin, 72 Mich. App. 212; 249 N.W.2d 360 (1976). An apparent minority of jurisdictions hold that there is no difference between a grant and a reservation for the purposes of implying an easement from an existing servitude or quasi-easement, and that only reasonable necessity is required for both. Despite the holdings in the cases cited above, this seems to be the most recent position adopted by our Supreme Court. In Harrison v Heald, supra, the Supreme Court was faced with the question whether the rules governing easements by implied grant also controlled implied reservation of easements. The Court quoted language from Rannels v Marx, supra, which Rannels had in turn quoted from Rischall v Bauchmann, 132 Conn. 637; 46 A.2d 898; 165 ALR 559 (1946), and noted that the language used, including that referring to an element of reasonable necessity, applied equally to grants and reservations. The Harrison Court was criticized for relying on dicta rather than its own prior holdings in reaching this result, and alternatively for failing to adopt the new course after squarely addressing the issue. While it is true that the Supreme Court in Harrison did not specifically direct itself to the precise issue of what quantum of necessity was to be required in cases of implied reservations, as opposed to implied grants, it is clear that it intended the same rules to apply to each. We thus view Harrison as controlling, and as requiring only a showing of reasonable necessity, regardless of whether a grant or reservation is sought to be implied. To the extent that post- Harrison decisions of this Court may be read to require a showing of strict necessity when an implied reservation is involved, it is our opinion that they were wrongly decided. See, e.g., Wilson v Anglin, supra, Kahn-Reiss, Inc v Detroit Northern Savings Loan Ass'n, supra.

Applying a test of reasonable necessity to the facts of the instant case, we hold plaintiff sufficiently established this element. The trial court found that the several alternative drainage plans open to the plaintiff would require considerable work. One of the expert witnesses who testified placed the cost of a new drainage system at between $30,000 and $35,000. Under the facts and circumstances of this case, the effort and expense were great enough for implication of the easement to be reasonably necessary.

B. Apparentness

In order to establish his easement, plaintiff also needs to show that it was apparent at the date of severance. The testimony conflicted as to whether the drain existed prior to November 12, 1968, the date of the lease, but the trial court found that it did not, that it instead came into existence in 1969. The lease contained an option to purchase the property, and on June 22, 1973, the defendants purchased the property they had been leasing. Since the trial court held that the necessity element had not been established, it felt that it was unnecessary to decide the question of when severance took place, but remarked that if called upon to do so, the appropriate date of severance would have been the date of the lease. Since we reach a different result on the necessity element, we must decide the date of severance. If, as the trial court suggested, that date is the date of the lease, then plaintiff has failed to establish the element of apparentness since the drain was found to have first come into existence after the date of the lease. If, on the other hand, the plaintiff is right in asserting that severance did not take place until 1973 when defendants took title to the land, then the easement was apparent and plaintiff will have shown all the elements necessary to the establishment of an implied easement.

We have found no Michigan cases directly on point, but our analysis of the purpose of the severance requirement leads us to conclude that the appropriate date of severance is the date of the lease.

Simply put, a severance is required because it is legally impossible to have an "easement" in your own land. If a person owns two adjacent tracts of land and imposes a servitude on one tract for the benefit of the other, there exists only a quasi-easement that may ripen into a full easement when one of the tracts is conveyed. A lease is a conveyance of property for a term, and while the grantor retains a reversionary interest in the land, the right to use and possess the land has passed to the lessee. It is for this reason that while an easement cannot exist over one part of a person's land in favor of another part when both parts remain in that person's possession, an easement may exist when one part is conveyed to a lessee. See Powers v Harlow, 53 Mich. 507; 19 N.W. 257 (1884), 5 Restatement Property, § 475, p 2976 (Illustration 1). The Restatement's drafters, when addressing the issue of severance, wisely chose to speak in terms of the severance of a single possessory interest. 5 Restatement Property, § 474, pp 2972-2975. See Koller v Jorgensen, supra, 628. The lessor, having conveyed his possessory interest in a tract of land for a period of time, must establish his right to use an easement in the land conveyed in the manner generally provided for establishing easements. In the instant case the defendants took a possessory interest in the land in 1968. In 1973 they joined with this possessory interest all the other property interests in the land that the deed conveyed. Given the nature and purpose of the severance requirement, we hold that the date of severance cannot be placed in the middle of a continuous possessory interest, but must instead be placed at the point where the possessory interest first arose, which in this case is November 12, 1968, the date of the lease. Because the trial court found that the drain did not come into existence until 1969, we hold that it was not "apparent" as of the date of severance. Plaintiff thus failed to satisfy one of the necessary elements, and the trial court did not err in holding that he failed to establish an implied easement.

II.

Plaintiff also contends that the defendants are bound to accept water drainage from his lands under a natural flow theory. The trial court disagreed, and plaintiff now argues that the trial court's findings of fact and conclusions of law in this regard are not supported by the record.

It is clear that the owner of the lower or servient estate must accept surface water from the upper or dominant estate in its natural flow, and equally clear that the owner of the dominant estate may not require the owner of the servient estate to accept a greater runoff by increasing or concentrating the flow. Bennett v Eaton County, 340 Mich. 330; 65 N.W.2d 794 (1954), Cranson v Snyder, 137 Mich. 340; 100 N.W. 674 (1904), Lewallen v City of Niles, 86 Mich. App. 332; 272 N.W.2d 350 (1978). The testimony in the instant case indicated that as a result of the development of plaintiff's land, the water runoff onto defendants' land was greatly increased, perhaps as much as six times the natural flow. Under these circumstances, we see no reason to disturb the trial court's ruling. This is not an appropriate case for a natural flow theory.

III.

Plaintiff's final argument that he has an easement because the lease and deed each contained general language conveying the property subject to easements reserved to the grantor is without merit. The deed listed several specifically defined easements that were reserved to the plaintiff, but made no mention of the drain which is the subject of this appeal. There was no express easement in the drain as such, and, as noted above, plaintiff has failed to establish an implied easement.

Affirmed.