Sediment computations--Conversion of suspended-sediment concentration from parts per million to milligrams per liter


                                             January 5, 1972

QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO. 72,10

Subject: Sediment computations--Conversion of suspended-
         sediment concentration from parts per million to 
         milligrams per liter

Beginning with the 1972 W.Y., the attached table (table 1. ) 
of conversion factors will be used in converting suspended-
sediment concentrations from parts per million to milligrams 
per liter.  This table supersedes the table of conversion 
factors given in TWRI, Book 5, ch. C1, P. 4, and any other 
tables that may have been used in the past. Some criticism 
has been received because of the fact that concentration 
values, in mg/l, given in our basin-data report cannot, in 
some instances, be converted back to ppm to the accuracy 
stated; that is, to three significant figures.

A revised TWRI, Preparation of Water-Quality Data Reports, 
Book 9, ch. B1, is being issued shortly, in which a 
conversion table (table 2) will be given to enable the data 
user to convert concentration in mg/l to concentration in 
ppm. Some data users apparently need ppm values rather than 
mg/l values for special studies.

Those districts that have already computed sediment 
concentration for the period October 1, 1971 through December 
31, 1971 need not necessarily recompute concentration values 
based on the new factors; however, it is recommended that for 
continuity they be recomputed if time permits. The new 
factors will be required beginning January 1, 1972



                           W. H. Durum
                           Chief, Quality of Water Branch

Attachments

WRD Distribution:
A, B, FO-L