585 



tive methods is necessary in order that management agencies can ap- 

 proach water quality problems in a given estuary without first 

 mounting a large-scale, expensive, and time consuming field investiga- 

 tion to define the assimilative capacity of the estuary through classical 

 methods. Inputs into such a technique, of course, demand knowledge 

 of the sources, characters, amounts, and time distribution of polluting 

 discharges, including urban and agricultural land runoff as well as 

 discrete sources. 



At the other end of the estuary is the exchange with the ocean. The 

 hydromechanical exchange which occurs between the estuary and the 

 ocean is an extremely complex phenomenon about which little is 

 known. This is a significant factor in the loss or retention of water 

 quality constituents in the estuary and is related to all of the other 

 discussion on hydraulics, sedimentation, and other physical aspects. 

 All kinds of modeling activity require qualitative and quantitative 

 data on ocean exchange, particularly in areas like Monterey Bay which 

 have an ill-defined interface with the ocean. 



Ground water 



Not to be overlooked in any investigation of the hydraulics of an 

 estuary is an understanding of the ground water to surface water re- 

 lationships, including subsurface water discharges and salt intrusion. 

 This calls for knowledge and quantification of the chemical and physi- 

 cal characteristics of ground water and ground water flow in the 

 estuaries. 



Engineei^g controls on water movement 



A natural sequence of an understanding of the hydraulics of an 

 estuary w ould be the utilization of this knowledge in engineering con- 

 trols on water movement. Apparently, little work has been done to take 

 advantage of the energy contained in the moving water for the pur- 

 pose of flushing and bottom-cleansing action. The research question 

 would be : "Is it possible to design engineering works that utilize water 

 movements, including, tidal action of estuarial flushing and bottom- 

 cleansing?" This question warrants investigation. 



SEDIMENTATION 



Substantial pollution problems in estuaries result from the effects 

 of benthic deposits. These in most estuaries represent a heritage of 

 pollutional materials brought in over the years by streams, outfalls, 

 and sewer overflows discharging into the estuaries. Research is called 

 for to provide an adequate knowledge of how to prevent and control 

 the effects of this material. Such research should be directed to meth- 

 ods for determining the origin of bottom deposits, their physical char- 

 acterization, acceptable measurement techniques, transport phe- 

 nomena, effect on the ecology of the system, and the die-away and. 

 fate of these materials. The ultimate question is, of course, how to 

 prevent undesirable sedimentation from increasing and how to get rid 

 of existing dej)Osits economically and efficiently. It may well be that 

 practical solutions to this problem will not be forthcoming. In this 

 case, dependable information on the natural die-away characteristics 

 of bottom deposits would be very desirable. Studies should be made 



