(1) Any land or water use for agriculture or animal husbandry as defined in the ordinances adopted by the governing authority, provided that a buffer of natural vegetation is maintained for a distance of 50 horizontal feet from the bank of the watercourse;

(2) Ordinary maintenance and landscaping operations, except for a distance of 50 horizontal feet from the bank of the watercourse and except for the removal of healthy trees over two inches diameter breast height (DBH) anywhere in the stream corridor;

(3) Any land or water use or project which, on March 16, 1973, is approved, pending, or is completed, actually under construction, or which is zoned for such use and where expenditures in excess of $2,500.00 have been made in preparation for construction in accordance with such zoning; provided, however, that the construction of the project is actually commenced within 36 months of March 16, 1973; otherwise, a certificate for the project must be obtained pursuant to this part;

(4) (A) With regard to any land included in the stream corridor for the first time after March 1, 1983, any land or water use or land-disturbing activity:

(i) Which, on March 1, 1983, is completed, under construction, fully approved by the governing authority, or for which all requests for approval of construction are pending before the governing authority; or

(ii) Which is to be located on land which, on March 1, 1983, is zoned for such use and where expenditures in excess of $2,500.00 have been made in preparation for construction in accordance with such zoning; provided, however, prior to March 1, 1984, construction of such land-disturbing activity must have actually commenced and expenditures must have been made in connection with such construction in excess of 10 percent of the estimated cost of the total projected land-disturbing activity, exclusive of the cost of the land, or in excess of $100,000.00, exclusive of the cost of the land, whichever is less; otherwise a certificate for the project must be obtained pursuant to this part.

(B) Upon request by the owner of any land included in the stream corridor for the first time after March 1, 1983, the commission shall make a determination whether any land or water use or land-disturbing activity on such land satisfies the conditions set forth in this paragraph for exclusion from application of this part. Any such request shall be accompanied by any information concerning the land or water use or land-disturbing activity as the commission may reasonably request. If the commission determines that the land or water use or land-disturbing activity fails to satisfy the conditions set forth in this paragraph, the commission shall state the reasons therefor. The commission shall be authorized to delegate this authority to its executive director. If such delegation is made, any person aggrieved by any such determination of the executive director may appeal such determination to the commission within 30 days of the issuance of such determination;

(5) (A) With regard to any land included in the stream corridor for the first time on or after July 1, 1998, any land or water use or land-disturbing activity:

(i) Which on July 1, 1998, is completed, under construction, fully approved by the governing authority, or for which all requests for approval of construction are pending before the governing authority; or

(ii) Which is to be located on land which, on July 1, 1998, is zoned for such use and where expenditures in excess of $5,000.00 have been made in preparation for construction in accordance with such zoning; provided, however, that prior to July 1, 1999, construction of such land-disturbing activity must have actually commenced and expenditures must have been made in connection with such construction in excess of 10 percent of the estimated cost of the total projected land-disturbing activity, exclusive of the cost of the land, or in excess of $100,000.00, exclusive of the cost of the land, whichever is less; otherwise a certificate for the project must be obtained pursuant to this part.

(B) Upon request by the owner of any land included in the stream corridor for the first time on or after July 1, 1998, the commission shall make a determination whether any land or water use or land-disturbing activity on such land satisfies the conditions set forth in this paragraph for exclusion from application of this part. Any such request shall be accompanied by any information concerning the land or water use or land-disturbing activity as the commission may reasonably request. If the commission determines that the land or water use or land-disturbing activity fails to satisfy the conditions set forth in this paragraph, the commission shall state the reasons therefor. The commission shall be authorized to delegate this authority to its director. If such delegation is made, any person aggrieved by any such determination of the director may appeal such determination to the commission within 30 days of the issuance of such determination; or

(6) Any land or water use or land-disturbing activity which is undertaken or financed, in whole or in part, by the Department of Transportation of the State of Georgia.