At the time of filing an application for right-of-way, the applicant must deposit with the Secretary the total estimated consideration and damages, which shall include consideration for the right-of-way, severance damages, damages caused during the survey, and estimated damages to result from construction less any deposit previously made under Sec. 169.4. In no case shall the amount deposited as consideration for the right-of-way over any parcel be less than the amount specified in the consent covering that parcel. If in reviewing the application, the Secretary determines that the amounts deposited are inadequate to compensate the owners, the applicant shall increase the deposit to an amount determined by the Secretary to be adequate. The amounts so deposited shall be held in a ``special deposit'' account for distribution to or for the account of the landowners and authorized users and occupants of the land. Amounts deposited to cover damages resulting from survey and construction may be disbursed after the damages have been sustained. Amounts deposited to cover consideration for the right-of-way and severance damages shall be disbursed upon the granting of the right-of-way. Any part of the deposit which is not required for disbursement as aforesaid shall be refunded to the applicant promptly following receipt of the affidavit of completion of construction filed pursuant to Sec. 169.16.