WATER LOSSES FROM WET AREAS 149 



the moist flats of the rivei- bottom, anions which are Ci/pcnts laeviaatus, Cyperus 

 esculcjitus, Elcocharis capitata, Elrocharis acicularis, Elcocharis montana, ticirpun 

 vernus, Carex praegracilis, JuncJis balticus, Juncus hufonius,, Juncus torreyi, Junc^is 

 ruoiUosus, and Juncus xiphioides. Other plants gi-owing on the moist flats with the 

 sedges and rushes are Equisflion funst<niii, Dislichlis spicaiu, ISporobolus aspcrijolius, 

 Sporobulus airoidcs, Cynodon davtylon. Paspaluvi distichum, Ccnchrus pauviflorus, 

 Anemopsis cdUfornica. Jxanuiiculus cymbakiris, Psoralea orbicularis, Psoralea macros- 

 tachya. Lythrutn califoruicu»i. Kpilubiu»i californicum, llydrocotyle ranunculoides, 

 Hydrocotylc umbcUata, Hydrocutyle vcrticillata, Eustoma silcnijolimn, Lippia lanceo- 

 lata. Petunia parviflora. Mirnulus cardinalis, Plantago hirteUa. Solidaffo occidentalis. 

 Aster exilis, Baccharis emoryi, Bacchai-is viminea, Pluchea camphorata, Antemisia 

 vnlc/aris. var. hcterophylla. On the sandy flats of the liver bottom grow four species 

 of Willow — Salix laevigata, Salix nigra var. valUcola, Salix argophylla, and Salix lasio- 

 lepis, besides Populus frcmontii, I'opulus trichocarpa, Alnus rhombifolia, and Pla- 

 tanus racemosa." 



The species found in this area are representative of the entire area 

 between the Riverside Narrows and Prado gaging stations. 



Stream flow records. 



In the area discussed in this report tliere are five gaging stations 

 maintained by the United States Geological Survey. The first of these 

 stations, established in 1919 at the Orange-Riverside County line, is 

 known as the station on the Santa Ana River near Prado. In 1929 a 

 station was established at Riverside Narrows. During the summer 

 periods since 1930 stations have been maintained at Hamner Avenue, 

 the Auburndale Bridge and The Atchison, Topeka & Santa Fe Railway 

 Bridge. The installations at these three stations are removed during 

 the winter, and the location of the stations is subject to a slight change 

 from vear to vear because of changes in the character of the channel. 

 The approximate location of each of these stations is shown on 

 Plate I. 



In order to determine the source of the gain in discharge of the 

 Santa Ana River between Riverside Narrows and Prado, two series 

 of discharge measurements, in June and August, 1931, were made 

 at numerous points along the river. The results are given in Table 2. 

 Additional miscellaneous measurements were made at many of these 

 points during 1931 by the Orange County Flood Control District and 

 the United States Geological Survey, and the results are given in 

 Water-Supply Paper 721 of the Geological Survey. 



Table 2 shows that the minimum flow is at some point below the J 

 diversion ditch and above the old Pedley power house of the Southern 

 California Edison Company. On both dates the flow decreased 10 

 second-feet or more in the first 6-mile stretch of the river channel below 

 Riverside Narrows. Much of this loss might have been caused by 

 the demand made on the water supply by the trees and other vegetation 

 along the river. Not only was the 10 second-feet lost, but any addition 

 that might have been made to the flow of the river in this area from 

 underground sources w^as also consumed. 



This table shows that from tlie Pedley power house to The Atchison, 

 To|)eka & Santa Fe Railway Bridge the Santa Ana River is a gaining 

 stream. The point of maximum flow is at or near the railway bridge. 

 There are very few visible springs in the area, most of the water enter- 

 ing the gravel in the bed of the stream. Hamner Spring is the only 

 spring of any size that contributes to the flow. 



If it were not for the natural losses, which are accounted for by 

 plant life, the gains showm in Table 2 would represent the entire con- 

 tribution of the areas adjacent to the river on the two days given. As 

 this contribution, during the summer, is entirely in the form of ground 



