LOWER 



BARRET , 

 RESERVOIR / 



California 



N 



MORENA 

 RESERVOIR ' 



\ UNITED STATES 



I f C "mexico 



10 15 Kilometers 

 ■4 — Dams 



SAN 

 JUAN 

 DE DIOS 



*., < 



Figure 1.1. Location of Tijuana Estuary and map of watershed. Stations are indicated where 

 rainfall and precipitation were measured (from IBWC 1983). 



period, marine waters submerged the Tijuana 

 River valley. Sediments that were brought 

 downstream from the watershed spread out 

 between the coastal mountains to create a 

 small but well-defined coastal plain (Figure 

 1.2). The action of wind and waves gradually 

 built up a sandbar and dune system parallel to 

 the coast, and formed a semi-enclosed body of 

 water. The area where marine waters are 

 intermittently mixed with fresh water from 

 Tijuana River is a small estuary immediately 

 adjacent to the coast. 



In other respects, Tijuana Estuary is very 

 different from most of the world's estuaries. 

 It does not fit well within the salinity 

 characterization schemes that have been 

 developed to describe estuarine embayments 

 (Davis 1978). Estuaries can be divided into 

 salt-wedge (river-dominated), partially 

 mixed (salinity gradient downstream), or 

 vertically homogeneous (brackish water 

 throughout) types. They can also be 

 distinguished by their salinity profiles as 

 either positive (fresh water floating over 

 saline water) or negative (warm saline water 

 floating over cool fresh water). As we 



