Flows and Recretion: A guide to studies for river professionals

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Objective Summarize recreation - relevant hydrology, describe project "plumbing," and identify existing and potential operational constraints on existing or alternative flow regimes. Typical approach Search for relevant summary hydrology data, usually from the USGS, state water resource departments, land managing agencies, and utilities. Assemble and summarize recreation - relevant findings that may include graphs and tables for typical or example recreation seasons. Product Summary hydrology section in a report. ts4o t4Q0 i20D tt00 U*O 900 em 700 ow ;40 300 2W Xau 0 Fibw in ds Hydrology Summary Responsibilities Utilities (or their consultants) have primary responsibility, but agencies may be able to provide access to key hydrology data or summaries to make this effort efficient (and non - duplicative). Additional issues The amount of analysis and presentation involved in this task depends on the resolution needed. For a Level 1 report, summaries of existing information or example hydrographs from an average year may be adequate; more intensive analyses and presentations are usually necessary to reach a higher degree of precision common for a Level 2 or 3 effort. Cautions & limitations Daily, monthly, or annual averages are often used to summarize hydrology, but these statistics may be insufficient if they mask important variability. For example, averages at a daily peaking facility may not reflect a flow that occurs for any substantial length of time. In nearly all cases, summary hydrology data for a key gage or hydrology reports for the larger relicensing effort will not be sufficient. Raw hydrology data, gage statistics, project operational constraints, and similar information commonly need to be "re- packaged" to focus on recreation - relevant flows or seasons. The goal is a clear and concise summary to illustrate how the system works or could be operated to provide flows for recreation. Lower Kern River Flaws, Summer 2003 May 24 My ai An 7 An U ,AP 21 1n 29 Ai 5 Ai V JU I JkA 26 ALq 2 dug 9 Aug 16 Aug 23 Au9 70 Sea 0 Labeled dater are Saturdays Shaded ,rerdeal bare are weekends or h6dayi Summarizing recreation - relevant hydrology usually involves re- organizing hydrology records. Above. Daily hydrographs for two segments on California's Lower Kern River illustate variable irrigation releases coupled with a steady hydropower diversion. Orga- nizing information for an example recreation season shows how flows drop on weekends (adversely affecting boating). Flows and Recreation: 11 A Guide for River Professionals