July 5 (Reuters) -Basis bids for soybeans and corn shipped by barge to U.S. Gulf Coast terminals held steady on Friday in quiet trade following Thursday's July Fourth holiday, traders said.

* Market players continued to monitor high water and flooding on the upper Mississippi River that has interfered with barge loading at riverside grain elevators.

* Eight locks and dams on the Mississippi River between Dubuque, Iowa, and Canton, Missouri were closed due to flooding, according to a U.S. Army Corps of Engineers website.

* However, weak exporter demand for grain at the Gulf muted the impact of the closures, traders said.

* CIF soybean barges loaded in July were bid at 73 cents a bushel over Chicago Board of Trade (CBOT) August SQ24 futures, unchanged from Wednesday.

* FOB export premiums for soybean shipments loaded from the Gulf in August were quoted at around 88 cents over CBOT August futures, steady with Wednesday.

* For corn, CIF barges loaded in July were bid around 53 cents over CBOT September CU24 corn futures, unchanged from Wednesday.

* FOB offers for corn shipments loaded from the Gulf in July were unchanged at around 61 cents over CBOT July CN24 futures and premiums for August loadings held at around 63 cents over September futures.

* The U.S. Department of Agriculture (USDA) reported export sales of U.S. old-crop corn in the week ended June 27 at 357,200 metric tons, below a range of trade expectations for 500,000 to 900,000 tons. New-crop corn sales totaled 311,500 tons. EXP/CORN

* Export sales of old-crop soybeans for the week totaled 228,400 metric tons, at the low end of trade expectations, and new-crop soybean sales totaled 150,300 tons. EXP/SOY

* Weekly wheat sales totaled 805,300 metric tons, the USDA said, topping a range of trade expectations for 350,000 to 700,000 tons. EXP/WHE

Reporting by Julie Ingwersen; Editing by Krishna Chandra Eluri

For displays of CIF basis, click on the codes in brackets: U.S. CIF Gulf soybeans GRYM U.S. CIF Gulf corn GRYN U.S. CIF Gulf SRW wheat GRYO U.S. CIF Gulf HRW wheat GRYP
For displays of FOB basis, please click on the following codes in brackets: U.S. FOB Gulf corn GRZC U.S. FOB Gulf soybeans GRZD U.S. FOB Gulf SRW wheat GRZE U.S. FOB Gulf HRW wheat GRZF LINKS Corn prices page: cpurl://apps.cp./cms/?pageid=corn-cash-market
Wheat prices page: cpurl://apps.cp./cms/?pageid=wheat-cash-market
U.S. barge freight BG/US
U.S. export sales estimates USDA/EST
U.S. grain export summary GRA/U
Brazil soybean export prices SYBS
Brazil corn export prices SYBX
Argentina grain prices GRA/ARG
Russia grain prices GRA/RU