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These data are common to both Manning equation and rating curve approaches to hydraulic simulation (with exception of velocity, as noted). If the rating curve approach is used, only the stage-discharge and velocity distributions need to be measured on subsequent trips to the field. GUIDELINES FOR EFFICIENT DATA COLLLECTION Experiences within the Instream Flow Group (IFG) have shown that certain procedures and types of apparatus can greatly increase consis- tency and efficiency of data collection. Some of these are mentioned irT the text, but are important enough to be repeated. 1. Once duties of members of the field crew have been assigned, they should not be changed. While a change in duty may reduce boredom, it also introduces minor discrepancies in field techniques which can accumulate to significant errors. A minimum of two people is required for a crew. Three or four people are desirable. Crews of more than four people tend to be rather inefficient. 2. Use a standard survey notebook for taking field notes. The rag paper will hold a written image even if dropped in the water, and may be used during rainstorms. The notebook design helps prevent the loss of pages. As a footnote, the person taking data ought to have legible handwriting and be able to add and subtract accurately. Be sure to take notes in pencil, and cross out mistakes • do not erase. Use 3H pencil or harder lead to avoid smudging 3.. There should be more than one current meter per field crew. This will alleviate the problem of having two-thirds of the crew sleeping under a tree while velocities are being measured. 4. Avoid holding conferences around the level. The more people near the tripod, the greater the probability that the levelman will have. to re-level the instrument. 5. For large or noisy rivers, two small walkie-talkies greatly reduce the strain of communicating between river and bank. In most situations a citizen's band radio will suffice. However, near large population centers or heavily travelled highways, the volume of CB traffic may require the use of commercial band radios. Alternatively, a prearranged set of flag or hand signals can be used for long-range communication. 6. A small hand winch, or come-along, is extremely useful for stretching taglines across larger streams.