FISH PROTECTION ACTIVITIES AT PRADO DAM, CORONA, CA.

Transcription

1 San Marino Environmental Associates 560 South Greenwood Avenue, San Marino, CA (626) FAX (626) s FISH PROTECTION ACTIVITIES AT PRADO DAM, CORONA, CA. Prepared for: U. S. Army Corps of Engineers Prepared by: San Marino Environmental Associates Jonathan N. Baskin, Ph.D. Thomas R. Haglund, Ph.D. August 2008

2 Introduction The U.S. Army Corps of Engineers (ACE) is reconstructing Prado Dam, in the Santa Ana River, Corona, CA where the Santa Ana sucker (Catostomus santaanae), a federal Threatened Species, is known to occur. On July 1, 2008 it was necessary for the ACE to divert Santa Ana river flow from an old approach channel to the dam tower into a new channel so that the flow will pass through the new dam tower (see field diagram). SMEA and ECORP Consulting personnel were engaged to implement fish protection procedures during this diversion. Results On June 17 SMEA personnel examined the site to plan necessary protection procedures (see Photos 1 and 2). The stream segments to be dewatered included an approach channel about 500 feet long and 80 feet wide and an exit channel about 600 feet long and 250 feet wide. On the morning of July 1 a team of several SMEA and ECORP Fishery Biologists arrived at the site with the intention of deploying at strategic locations to rescue stranded native fishes, especially suckers, if necessary when the diversion occurred. However it was found that the actual diversion had already taken place a few minutes before our arrival. Many fishes were found stranded on the dry stream bottom, but none were native fishes. They were all non-native fishes, carp (Cyprinus carpio), black bullhead (Ameiurus melas) and fathead minnow (Pimephales promelas). Other non-natives fishes found were channel catfish (Ictalurus punctatus) and inland silverside (Menidia beryllina). Some minimal stream flow remained in the dewatered stream reach (approach channel) due to seepage of ground water and stream water through the diversion berm (see Photo 3.) Seines and dip nets were used to capture fishes here and in isolated puddles, and fifteen suckers were found (see Table 1). No other native fishes were found here. Seining continued until no more suckers were found, despite extensive effort. The exit channel downstream from the old tower was only partially dewatered. Not enough water was removed from this area to leave any fishes stranded because the area was much larger (broader and deeper) than the approach channel, with an extensive soft sediment bottom. (see Photo 4). Attempts by the construction contractor to remove the water by pumping had little impact. Seining at the downstream end of the area adjacent to the outflow, where the bottom was largely cobble or concrete with moderate flow and some riffle habitat, yielded only exotic fishes. The majority of the exit channel was inaccessible due to very soft bottom and deep water. It was determined that the water was not going down, even with pumping, so larger pumps were planned for use the next day. Upon returning on July 2 the water level in the exit channel was down significantly due to pumping (see Photo 5). Extensive seining was done, including the use of a 100 foot long seine. This yielded numerous non-native fishes and five additional suckers. Seining continued until no more suckers were found. Conditions in the dewatered approach channel were unchanged. All of the suckers found were weighed and measured, and released at the downstream end of the new exit channel, below a drop structure (see Photo 6 and Field Diagram). Two suckers were

3 found dead, and were preserved for deposit in the Los Angeles County Museum of Natural History. Table 1 gives the data on these fish. Condition Index is a measure of the body condition of the fish. Comparison of data on these specimens with data from suckers SMEA has captured in other areas of the Santa Ana River shows that the fishes are in good condition. Water quality parameters were measured on July 1 at 3:00 P.M. at the downstream end of the exit channel (see Photo 2): temperature 32.7 degrees C; conductivity 1.05 micro semens/square cm; turbidity 150 UTMs; dissolved oxygen 11.8 mg/liter, salinity 0.04%, ph All of these values are within the range of conditions appropriate for sucker with the exception of the turbidity, which is substantially higher than other places where we have found suckers. On July 2 nd the water quality parameters at the site where the suckers were released (see Photo 6) were, temperature 25.1 degrees C; conductivity 1.02 micro semens/square cm; turbidity 170 UTMs; dissolved oxygen 7.97 mg/liter, salinity 0.04 %, ph Photo 1. View upstream (northeast) of approach channel of Santa Ana River on June 17. Old tower is in foreground and Prado Basin in background. Section to be dewatered is indicated by the arrows.

4 Photo 2. Downstream end of exit channel on June 17. Note of new exit channel, not yet in use, in the background. In the foreground is the exit channel that will be dewatered on July 1. Note the riffle habitat (arrows) formed by the hard substrate, which is considered good sucker habitat.

5 Photo 3. View upstream on July 1 of the approach channel shortly after water was diverted into the new approach channel by the placement of a dirt berm across the stream just out of sight in the background indicated by the arrow. Note the extensive soft sediment bottom, and the remaining minimal flow and puddles where suckers were found.

6 Photo 4. View downstream of exit channel on July 1st. Area shown in Photo 2 is in the background (red arrow). Note extensive amount of water.

7 Photo 5. View of exit channel on July 2 nd following dewatering by pumping. Suckers were found near the concrete wall in the background.

8 Photo 6. View downstream of Santa Ana River just downstream of the new exit channel. Arrow shows site of sucker release.

9 Table 1. Santa Ana suckers captured in Santa Ana River at Prado Dam site, July 1-2, Location SL mm. weight gr. Condition Index approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel approach channel exit channel exit channel exit channel exit channel exit channel

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