Del. Code tit. 23 § 1509
The land under the waters of the Delaware River, within the limits as determined in § 1510 of this title, on the front of the littoral holdings of the littoral proprietors, respectively, and between the bulkhead line or lines of solid filling, as shown and exhibited on the maps referred to in § 1505 of this title, and the westerly bank of the river (designating the high watermark thereof), shall vest in fee in the littoral proprietors, their heirs, executors, administrators, successors and assigns, respectively. When a suitable bulkhead has been constructed in front of any of the littoral holdings of any of the littoral proprietors, the Attorney General, upon satisfactory evidence of that fact, and the tender to the Attorney General of the reasonable and necessary expenses of preparing the conveyance or conveyances named in this section, shall seasonably prepare and forthwith execute under the seal of the State a grant assuring to the littoral proprietors, respectively, their heirs, executors, administrators, successors and assigns the lands under water in front of their respective littoral holdings between the bulkhead line and the river bank.
23 Del. C. § 1509