Major Obstacles to Harbor Deepening (Cont'd) 



Harbors 



Authorized 

 Depth' 



Major Reloca 



tions and 

 Dislocations^ 



Rock and/or 



Continental 



Shelf^ 



Spoil 

 Disposal^ 



Ecology 



Escanaba Harbor 



Gary Harbor 



Sandusky Harbor , 



Lorain Harbor 



Cleveland Harbor , 



Ashtabula Harbor 



Conneaut Harbor 



Erie Harbor 



Buffalo Harbor 



Huron Harbor 



Detroit River 



St. Clair River 



Straits of Mackinac 



Toledo Harbor 



St. Mary's River 



Trenton Channel, Detroit River 



Saginaw River 



Muskegon Harbor 



(Beginning depth of problem— in feet) 



Authorized depth is the channel depth in feet to which harbor deepening has been authorized by law. It Is not 

 necessarily the actual or controlling depth which presently exists. 



Relocations and dislocations are the depths which'channels would affect existing shorelines, wharves, or other installa- 

 tions. See Section Vll-C of Chapter 5. 



^This is the depth at which bedrock or other heavy material underlying the softer sedimentary overburden is reached. 

 The cost of dredging beyond this depth becomes substantially greater. 



This depth in feet shows the channel depth at which the disposition of dredge spoil becomes a significant problem. See 

 Section Vl-E of Chapter 5. 



Damage to water supplies, either by salt water intrusion or damage to aquifers. 



Includes loss of fish and wildlife habitat, destruction of unique geological areas or plant life, etc. 



•7 



Pollution problem. 

 Source: U.S. Army, Corps of Engineers, Office of Civil Works. 



111-169 



