The General Assembly shall enact no law authorizing private property to be taken for public use without just compensation, to be agreed upon between the parties or awarded by a jury, being first paid or tendered to the party entitled to such compensation, except that where such property, located in Prince George's County in this State, is in the judgment of the Washington Suburban Sanitary Commission needed for water supply, sewerage and drainage systems to be extended or constructed by the said Commission, the General Assembly may provide that such property, except any building or buildings may be taken immediately upon payment therefor by the condemning authority to the owner or owners thereof or into the Court to the use of the person or persons entitled thereto, such amount as the condemning authority shall estimate to be the fair value of said property, provided such legislation requires that the condemning authority's estimate be not less than the appraised value of the property being taken as evaluated by at least one qualified appraiser, whose qualifications have been accepted by a Court of Record of this State, and also requires the payment of any further sum that may subsequently be awarded by a jury, and provided such legislation limits the condemning authority's utilization of the acquisition procedures specified in this section to occasions where it has acquired or is acquiring by purchase or other procedures one-half or more of the several takings of land or interests in land necessary for any given water supply, sewerage or drainage extension or construction project.