Evaluation of Historical Sediment Deposition 



Timber Harvest • — • 

 (5 Yr cumulative amortized acreage) 



2000 4000 6000 8000 



« Insert Figure B-2» 



Flood. 

 Fire 



1990- 



1980 



1970- 



1960- 



Swan Highway Constructed 1950^ 

 Logging resumed — 



1940 1 

 Fire — 



1930 



Logging declines 



1920 • 

 Road built along Swan Lake, Fire — 



Log Drives & Railroad Logging begins 



Fire — 1910- 



1900-1 

 flood — 



1890 



1880-1 

 1870 



10 20 



Mean Sedimentation Rate 

 ,2 



(mg/cm'^/yr) 



Figure B-2. Mean sediment accumulation rates in Swan Lake over the last 125 years, 

 and timber harvest activity over the time period (since 1948) when harvest records 

 could be assembled. This latter activity is expressed as a 5 year cumulative acreage, 

 with previous 4 years acreages amortized using the Flathead National Forest new road 

 sediment delivery coefficients. 



Page 30 



Flathead Basin Cooperative Program Final Report 



