C150273 Feasibility Study

• Contract/PO #: C150273
• Contractor Name: Ogilvy Augmentation Company
• Contract Type: Loan
• Water District: 0
• County: Weld
• Loan Projects - Doc Type: Feasibility Study

The proposed location of the recharge reservoir is shown in Figure 2. The recharge reservoir will be
constructed with side slopes of 2H:1 V that extend from the natural ground surface to the free
draining soils located above the aquifer. To protect against storm water a 2 foot high berm will be
constructed surrounding the excavated reservoir. The augmentation water to be delivered to the
recharge reservoir is proposed to be delivered using a head gate and pipeline installed along the
Ogilvy Ditch system.
A geotechnical investigation of the proposed location indicated that a layer of clay material was
located in upper portion of the proposed location, See Appendix G for the geotechnical investigation.
The thickness of the clay layer ranged from 7 feet to 14 feet. The clay layer has a low permeability
and will need to be removed to facilitate the recharge of the underlying aquifer with augmentation
water.
A cost analysis for the construction of a one-half acre recharge reservoir is shown in Table 4. The
large expense for the construction of the recharge reservoir is associated with the excavation spoil of
unsuitable material in the recharge site.
TABLE 4
Cost Projection
(lnp_Nalf ArrP RPOharap Rpcervnir
Description Qty- Units Unit
]['rice Sub-Total Total
Insurance Bonds I LS $1,000.00 $1,000 $1,000
Mobilization/Demobilization I LS $2,000.00 $2,000 $2,000
Excavation/Spoil 13,550 CY $3.70 $50,500 $50,500
Inlet Structure
Headgate I EA $2,000.00 $2,000 $2,000
Pipeline 1 EA $500.00 $500 $500
TOTAL CONSTRUCTION COSTS $56,000
CONTINGENCY (20%) $12,000
ENGINEERING/LEGAL/SURVEYING $12,000
TOTAL $80,000
8.4 Storage Reservoir
The OAC is in need of reservoir storage space to store excess consumptive use credit from the GIC
shares delivered during the summer and releasing the credit during winter months to satisfy its
irrigation well augmentation requirements and winter return flow obligations associated with the GIC
shares. It is anticipated that a maximum storage space of 50 acre-feet is needed to meet the basic
Feasibility Study of the Ogilvy Augmentation Company Page 7
Well Augmentation Project