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Introduction Providing fish passage at Hartland Diversion Dam has been identified as an action item (11.132a) for the Gunnison River for 1995 in the Recovery Implementation Program's Recovery Action Plan (RIPRAP; U. S. Fish and Wildlife Service [USFWS] 1995). The following is a discussion that assesses the merits of providing fish passage at this structure for both candidate and endangered native fishes. Background Hartland Diversion Dam, located on the Gunnison River (RM 59.9) 3.6 river miles upstream of the Uncompahgre River confluence near Delta, Colorado, is a six-foot high structure that effectively restricts upstream movement of fishes during most flow stages (Figure 1). Fish might be able to pass upstream over this structure but only during extremely high flows. However, since construction of the Aspinall Units, the frequency of flows available to inundate the structure and allow upstream movement past the barrier has been reduced. The structure was constructed in 1881 for agricultural irrigation and stock-watering purposes and diverts 41-43 cfs through a headgate and canal on the north side of the river March through November. The dam spans the entire river, approximately 300 feet. It is constructed of railroad iron driven vertically into the river substrate and reinforced with steel and rip-rap. The structure was repaired and upgraded in 1942. The Hartland Irrigation Company owns the diversion dam and operates and maintains the headgate and irrigation canal. The City of Delta is proposing to "clean up" the existing structure because it is considered unsafe and is not passable by river enthusiasts (fishermen and boaters). The Hartland Irrigation Company does not have funding designated for this project. Therefore, joint funding sources may be required to implement this project. The City of Delta has the lead for investigating the possibility of removing the existing diversion structure, and engineering and developing a new diversion point. Although their intent is to provide river access and passage for boating enthusiasts, the City of Delta has guaranteed to first protect the irrigation company's water right. Therefore, complete removal may not be as likely as constructing a chute in the current structure to allow boat passage. The Service has contacted City of Delta officials indicating its support for this project. The Service has indicated that total or partial removal is probably desirable to pass fish. The feasibility of providing simultaneous boat and fish passage needs to be explored. These chutes may have to be separate, as an example, the key to enabling fish to ascend some swift chutes is rock placement and associated resting pools, which could be hazardous to boaters. The engineering feasibility to develop both types of passage needs to be explored. The Service has indicated support for the City of Delta proposal because,it appears compatible with planned enhancement and restoration of bottomland habitat adjacent to the Gunnison River in the Delta area to assist recovery of the endangered Colorado squawfish PIychocheilus lucius (USFWS 1973) and razorback sucker Xyrauchen texanus (USFWS 1973). The Recovery Program could consider a cost-sharing arrangement with the City of Delta and local recreational concessionaires.