148 



DIVISION OF WATER RESOURCES 



Between Riverside Narrows and the Prado gaging station the 

 Santa Ana flows tlirough an inner valley or flood channel in most 

 places less than a mile wide, cut in the old alluvial deposits. Flood 

 flows have deposited in this channel very absorptive gravelly material 

 to a depth of 80 to 100 feet. ]\Iost of this bottom land is now over- 

 grown with plant life, as shown on Plate I. 



Purpose of investigation. 



The purpose of this investigation was to determine the total 

 quantity of ground water that reaches the valley or flood channel of 

 the river in this area. It may be represented as the water passing 

 the points marked a in Plate II. This quantity of water would be equal 

 to the gain in the flow of the river if the losses by evaporation and 

 transpiration were reduced to zero. 



Classification of bottom land. 



The character of the plant cover of the bottom land between River- 

 side Narrows and the Prado gaging station is indicated on Plate I. 

 The various areas on this plate have been computed and the results 

 are given in Table 1. Between Hamner Avenue and The Atchison, 

 Topeka & Santa Fe Railway Bridge there are 2110 acres of river 

 bottom land, classed as the area of natural losses. Throughout this 

 area the water table ranges from ground surface to about 5 feet 

 below it. 



TABLE 1 

 CLASSIFICATION OF BOTTOM LAND ALONG SANTA ANA RIVER, 1933 



Classification 



Water surface 



Swamp plants, sedges, rushes, etc. 



Hea\'y brush cover 



Light brush cover. 



Heavj' tree cover 



Light tree cover 



Grass 



Cultivated 



Bare sand 



Total area, acres 



Hamner Avenue 

 to Atchison, 

 Topeka and 

 Santa Fe Rail- 

 way bridge 



Per cent 



5.5 



6.4 



7.1 



10.1 



34.9 



1.1 



23.7 



4.8 



6.4 



100.0 



2,110 



Riverside 



Narrows to 



Prado gaging 



station 



Per cent 



5.2 



6.0 



8.8 



11.9 



37.6 



2.3 



18.6 



3.4 



6.2 



100.0 



4,040 



Howell ^ amply describes part of the area between the RiA-erside 

 Narrows and Prado gaging stations. He classifies the flora as follows : 



"Submerged aquatics of the ponds include Potamogeton crispus, Zannichellia 

 palustris, Lenina trisulca, and Myriophyllum spicaUom, and the floating flora is com- 

 posed of such widely distributed species as Azolla fllicioloides, Lemna minor, and 

 Wolfiella Ungulata. In the shallow water of the marshes are found Typha angusti- 

 folia, Cyperus melanostacliyus, Eleocharis rostellata, Scirpus validus, Scirpus ameri- 

 canus. Polygonum hydropiperoides, Radicula luisturtinm-aquaticum,, Jussiaea cali- 

 fomica, Oenanthe sarm&itosa, Samolus floribundus, Lycopus aviericanus, Bidens 

 levis, and Helenium puherulum,. A large number of sedges and rushes are found on 



« Howell, J. T., The Flora of Santa Ana Canyon Region : Madrono, Vol. 1, 

 December, 1929. 



