Water Collection & Treatment Systems Case Study The Jemez Pueblo is located in north-central New Mexico, roughly 50 miles northwest of Albuquerque along the Jemez River which is tributary to the Rio Grande. The Pueblo is currently home to about 2,300 residents (2006), whose water supply needs are currently met by a system consisting of two groundwater wells, three water storage tanks, a filtration system, and approximately 16 miles of water distribution pipeline (2007 Preliminary Engineering Report). The Pueblo also has approximately 4 miles of wastewater collection pipelines, discharging into three wastewater treatment lagoons with a total surface area of 25 acres (2007 NRCE study). NRCE has worked with the Jemez Pueblo since 1994 to complete a variety of work related to the Pueblo’s water supply, wastewater treatment, and water planning needs, as well as work in other fields. Four studies are presented below which highlight the work NRCE has done for the Jemez Pueblo related to the field of storage, distribution, collection, and treatment systems.

Location Map of Jemez Pueblo. Water Source Engineering Study (1994) NRCE was contracted by the Pueblo of Jemez Indian Health Service to perform an engineering study for the immediate and long-term improvement of water quality for the Pueblo of Jemez. The Pueblo’s current (1994) domestic water supply from the Jemez Creek alluvium was analyzed in terms of quality and quantity, and compared to the future anticipated domestic water needs of the Pueblo for planning purposes. The study consisted of six components: (1) an evaluation of the water quality conditions of the Pueblo water supply, (2) a laboratory study of pre-distribution treatment options for the

Pueblo water supply, and potential treatment problems unique to the Pueblo based on water chemistry; (3) a quantification of water supply requirements necessary to meet the future domestic water needs of the Pueblo, based on a 20-year projection of Pueblo population and per-capita water uses; (4) a water development plan outlining infrastructure components to be constructed at various stages over a 20-year planning period; (5) an estimation of capital and annual operation and maintenance costs for all aspects of the proposed water development plan; and (6) a hydraulic analysis of the current and future water supply and distribution system, using hydraulic simulation computer software to estimate flow rates and pressures at specific points in the system. The study provided the Pueblo with important information regarding the quality and quantity of their current and potential water supply sources, and changes in water supply sources and distribution system that will likely be required over the 20-year planning period. Jemez Wastewater Expansion Study (2005) The Jemez Pueblo is currently (2007) served by three non-discharging lagoons for wastewater treatment. The lagoons are undersized and the wastewater treatment system as a whole is in need of upgrading to handle the current wastewater flows and the expected increase in flows due to population growth. NRCE was contracted to undertake an investigation of possible solutions to the Pueblo’s wastewater treatment problems based on a year 2025 planning horizon. The Pueblo’s increasing wastewater treatment needs were estimated based on a projection of Pueblo population growth and estimates of per-capita wastewater generation. In addition, a floodplain analysis was completed to investigate treatment location and land application concerns, and evaporation rates in the lagoons were also evaluated. The potential life of the existing lagoons in meeting the present and future needs of the Pueblo was evaluated using a spreadsheet hydraulic model of the lagoons. The increased evaporation caused by the addition of solar-powered air circulators in the lagoons was investigated using the model, because the Pueblo had recently added two circulators at the time of the study. The results indicated that the addition of two circulators might extend the life of the lagoons to the year 2016. The results of the lagoon modeling are shown in Figure 2 in the report (shown below).

NRCE examined the issue of the best long-term solution to the Pueblo’s wastewater treatment problems by reviewing the results of previous planning efforts and preparing an alternative evaluation for a variety of wastewater treatment facilities. Alternatives considered in the evaluation included: (1) adding solar-powered air circulators into the existing lagoons to increase evaporation, (2) land application, (3) new lagoon(s), (4) increasing the size of the existing lagoons, (5) constructed wetlands, and (6) a mechanical wastewater treatment plant. Each alternative was evaluated in terms of capital and annual costs, as well as the alternative’s ability to meet the present and future wastewater treatment needs of the Pueblo. Construction, O&M, and other considerations were compiled for a variety of wastewater treatment solutions and presented to the Pueblo for consideration. Table 14 in the report summarizes the cost estimates for the alternatives considered.

A separate study completed in 2007 investigated the costs and options for conventional wastewater treatment on the Pueblo. The study investigated the use of treatment technologies such as activated sludge, attached growth (trickling filter), and sequencing batch reactor systems to serve the estimated Pueblo wastewater generation rate of 0.3 million gallons per day (mgd) in the year 2040. Present value costs of future capital,

operation, and maintenance were calculated. Tables 13 and 14 in the report (shown below) summarize cost information from the U.S. Environmental Protection Agency (EPA) and Border Environment Cooperation Commission (BECC). In addition, costs and options for the disposal and/or use of treatment biosolids and effluent were evaluated.

Water Master Plan (2002) The Jemez Pueblo desired to have a tool for their water resources development planning, and NRCE was contracted to complete a Water Master Plan in 2002. The Water Master Plan was a comprehensive analysis of the Pueblo’s water supplies and demands over a 50-year planning period. The plan was divided into four sections: (1) a water resources assessment, (2) a water demand assessment, (3) a community water system evaluation of both present and future infrastructure, and (4) a cost analysis for future water system development. The water resources (supplies) available to meet the needs of the Pueblo were categorized as primary sources and secondary sources, based on flow rates and water quality. The Pueblo’s primary sources of water were identified as the Jemez River and the adjacent alluvial aquifer. Secondary sources included tributary streams, the deeper Santa Fe aquifer, and groundwater springs. The water demand assessment was divided into agricultural and non-agricultural water uses. Agricultural water uses were characterized based on crop water requirements, irrigated acreages, and irrigation efficiencies. Non-agricultural water uses included water for domestic needs, economic development, and recreation; calculated based on population projections and per-capita rates of water consumption. It was anticipated that the Pueblo’s future water demands would increase with population, and increase on a per-capita basis as development occurs on the Pueblo, as shown in Figure 3-2 in the report (shown below).

The present infrastructure making up the community water supply system was inventoried and evaluated, meeting with Pueblo members and conducting field visits. A map of the existing system is shown in Figure 5-1 of the report (shown partially below).

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The calculated water demands of the Pueblo were compared to the current water supply system’s capacity to meet those demands. System components such as sources, water treatment, storage, and distribution (capacity and pressure) were analyzed through hydraulic modeling in WaterCAD. Future improvements such as well development, water treatment expansion, pipeline expansion and development, and construction of storage were discussed. Water system improvements were categorized as near-term or long-term, ranked in priority, and assigned costs and potential funding sources, as shown in Table 6-1 in the report (shown below). As part of the Water Master Plan, a drought contingency plan was developed for the Pueblo.

Owl Springs Reservoir Feasibility Study (2007) Owl Springs Reservoir is being considered as a possible water storage project to enhance the water supply available to the Jemez Pueblo. The proposed dam and reservoir would be located in Owl Springs Canyon, on the west side (off-stream) of the Jemez River. The reservoir storage would enable the Pueblo to expand their irrigated acreage and possibly serve future economic development and domestic water needs. NRCE was contracted to conduct a feasibility study of the Owl Springs Reservoir project, to better understand the technical and economic feasibility. The study included: (1) preliminary designs for the various project components, (2) operational studies to determine available water supplies, (3) environmental and cultural assessments, (4) geologic and geotechnical investigations, and (5) cost estimates for project construction, operation, and maintenance. Figure 1-4 in the report (shown below) provides an overall layout of the project.

Water supply and operations modeling was completed using RiverWare and analysis of USGS gage data. The modeling indicated the currently available water supply from the Jemez River, and the increased water supply (and irrigated acreage) possible through the storage of water in Owl Springs Reservoir. The dam embankment was designed as a zoned earth-fill dam, as shown in Figure 5-2 of the report (shown below). Geotechnical and geologic investigations of the embankment and reservoir site were completed by Mark McKeown (former Senior Engineering Geologist with the USBR), and the local soils and geology were concluded to be conducive for dam construction. Dam stability and seepage were calculated using WinStabl and Seep2D software, respectively. Additional analyses of the dam and reservoir included sedimentation, outlet works design, and emergency spillway hydrology and design. The supply and delivery systems were designed as buried HDPE pipeline. Environmental and cultural surveys of the area were performed, concluding that the project’s impacts would likely be minimal and could

be mitigated. Capital, operation, and maintenance costs were estimated for the Owl Springs Reservoir project, and modified to present value costs using a design life of 100 years and a discount rate of 3.0 percent. Costs were estimated based on a compilation of USBR dam project costs, previous costs assessments for the Owl Springs project, and line-item unit costs based on the feasibility-level design.

Since 1994, NRCE has also provided additional services to the Jemez Pueblo in other fields, including:

• Water rights analysis and negotiation support as part of the Abousleman case involving the adjudication of water rights in the Jemez River Basin;

• An evaluation of the current irrigation system and completion of an irrigation

system rehabilitation plan;

• Hydrologic analyses of the Pueblo water supply, including an undepleted flow analysis of the Jemez River and various RiverWare modeling scenarios investigating natural, historical, present, and possible future water uses and allocations in the Jemez River Basin.