Table A-16. Summary of Significant or Potentially Significant Impacts of CRDRP

before Mitigation and Review of Mitigation Measures

Significant or Potentially Significant Impacts of CRDRP

Mitigation Measures (parentheses refer to sections from 1994 NLP EIR or 1998 SEIR)

Is Mitigation a Permit Condition?

Impact Level After Mitigation
Geology
G1. Erosion potential during construction. Implement approved Erosion Control Plan; obtain 1601 Stream Alteration Agreement from CDFG; carry out RWQCB Section 401 requirements (NLP 6.3.1-1)

Yes, SWRCB Permit 20808 Conditions #20, 21, 23 and 45;

COE 404 Permit 20364S09 Special Condition #2.

LS
HYDROLOGY  
H1. In drought years only, lack of flow to the lagoon in certain months. [Project provides flow benefits in most years.] Flow releases as required by SWRCB; year-round flow to lagoon not possible in drought years due to lack of inflow and release requirements for fish during winter and spring months. (NLP 7.3.1-1; SEIR C.3.1-1)

Yes, SWRCB Permit 20808, Condition #34 -37;

COE 404 Permit 20364S09 Special Condition #3.

SU in drought years only (<25% of time)
H2. Potential reduction in channel capacity and increased flood elevations downstream of dam. Carry out approved 20-year monitoring plan for changes in channel capacity and riparian vegetation growth. If adverse trend observed, implement agency-approved corrective measures such as selective channel clearing and sediment removal. (NLP 7.3.1-4)

Yes, SWRCB Permit 20808, Condition #22 and 45;

COE 404 Permit 20364S09 Special Condition #3.

LS
H3. Potential reduced sediment movement in mainstem may lead to buildup at confluence with tributaries and degraded fish habitat. Monitor sediment delivery for six major tributaries for 20 years; if adverse trend observed, implement corrective sediment management measures such as detention basins to trap bedload. (NLP 7.3.1-6)

Yes, SWRCB Permit 20808, Conditions #22, 33 and 45;

COE 404 Permit 20364S09 Special Condition #3.

LS
H4. Changed streamflow pattern potentially could increase sediment residence time and lead to streambank erosion. Monitor channel geometry and riparian growth for 20 years; if significant potential for erosion in storms is observed, implement corrective river works to reduce erosion risk (NLP 7.3.1-7)

Yes, SWRCB Permit 20808, Condition #22 and 45;

COE 404 Permit 20364S09 Special Condition #3.

LS
H5. Potential sand transport into the lagoon due to increased flow in dry years. Monitor lagoon volume and sediment transport for 20 years; if significant potential for habitat degradation is observed, implement corrective program to reduce sediment deposition. (NLP 7.3.1-8)

Yes, SWRCB Permit 20808, Condition #45 and 47;

COE 404 Permit 20364S09 Special Condition #3.

LS
H6. Impoundment of water in new reservoir could alter downstream water quality (esp. temperature and oxygen for aquatic life). Design and construct multi-level intake structure on outlet works that enables flexible operation to maximize releases of cool, oxygenated water. (NLP 7.5.1-1)

Yes, SWRCB Permit 20808, Condition #24 and 45;

COE 404 Permit 20364S09 Special Condition #3.

LS
H7. Temporary adverse impacts to water quality during dam construction. Implement RWQCB Section 401 Certification requirements, including water treatment, erosion control, construction practices, spill prevention plan vegetation buffer zones, water quality monitoring, protection of domestic supplies for nearby water users, agency coordination and special discharge permits prior to construction. (NLP 7.6.1-1 as refined)

Yes, SWRCB Permit 20808 Condition #23 and 45;

COE 404 Permit 20364S09 Special Conditions #2 and 3.

LS
Fish and Aquatic Life  
F1. New reservoir inundates or blocks 12% of steelhead spawning habitat. Restore existing degraded habitat downstream of new dam by injection of spawning gravels as described in Spawning Habitat Mitigation Plan. (NLP 8.3.1-1; SEIR D.4.1-1)

Yes, SWRCB Permit 20808 Conditions #32, 33, 43 and 45;

COE 404 Permit 20364S09 Special Condition #3.

LS
F2. New reservoir inundates or blocks 12-14% of steelhead rearing habitat. Flow releases, substrate and woody debris management as described in Steelhead Resource Mitigation Plan. (NLP 8.3.1-2; SEIR D.4.1-2)

Yes, SWRCB Permit 20808 Conditions #33-37, 43-45;

COE 404 Permit 20364S09 Special Condition #3.

LS
F3. In severe drought periods (such as 1987-1991), reduced opportunity for upstream migration as compared to natural conditions. [CRDRP is beneficial compared to existing/No Project] Flow releases as feasible, without impacting other portions of steelhead life cycle; operate emergency broodstock program, if approved by agencies. Impact cannot be mitigated with flow alone; if emergency broodstock facility not approved, impact cannot be fully mitigated. (NLP 8.3.1-3; SEIR D.4.2-1)

Yes, SWRCB Permit 20808 Conditions #33-37, 43-45;

COE 404 Permit 20364S09 Special Condition #3.

PSU in prolonged droughts only

(<12% of time)

F4. Project flows are beneficial for juvenile rearing except potentially significant in late spring and early summer between dams; potential impact of sediment buildup as described in H3. Operate reservoir to ensure releases to maintain fry downstream following emergence from nest; improve rearing habitat between Narrows and San Clemente Dam. Maintain passage of woody debris; manage sediment; rescue and rear fish in droughts. (NLP 8.3.1-5; SEIR D.4.2-3)

Yes, SWRCB Permit 20808 Conditions #33-37, 43-46;

COE 404 Permit 20364S09 Special Condition #3.

LS
F5. Reduction in winter and spring peak flows could change substrate conditions in three river reaches, and potentially reduce the abundance and diversity of preferred insect food sources for juvenile steelhead in those areas. Conduct monitoring and benthic surveys to estimate species richness, species diversity and population densities of benthic insects. If monitoring shows a decline in drifting insects, implement a program to inject appropriately sized riverbed material to increase bed mobility. (SEIR D.4.2-4) No. This information was developed after permits were issued in 1995 as part of settlement of litigation on SWRCB permit. LS
F6. Compared to natural conditions, increased risk of stranding fall and winter migrants. [Reduced risk compared to existing/ No Project conditions.] Flow releases required by SWRCB; rescue migrants when warranted by lack of flows, similar to existing program (NLP 8.3.1-6; SEIR D.4.2-5)

Yes, SWRCB Permit 20808 Conditions #33-38, 40, 43-46;

COE 404 Permit 20364S09 Special Condition #3.

LS
F7. Increased risk of stranding emigrating smolts in spring in certain critically dry years; risk duration would be longer in certain drought years, though total years with risk would be lower. Flow releases required by SWRCB; rescue smolts when warranted by lack of flows, similar to existing program (NLP 8.3.1-7; SEIR D.4.2-6)

Yes, SWRCB Permit 20808 Conditions #33-37, 40, 43-46;

COE 404 Permit 20364S09 Special Condition #3.

LS
F8. Compared to natural conditions (no human structures), adverse effects to fish passage. [Improved fish passage compared to existing conditions.] Design and construct facilities as approved by resource agencies; add screens as needed; water releases to keep San Clemente Reservoir full. (NLP 8.3.1-8; SEIR D.4.3.1-1)

Yes, SWRCB Permit 20808 Conditions #33-37, 41-45;

COE 404 Permit 20364S09 Special Condition #3.

LS
F9. Construction activities could damage fish habitat due to sedimentation and impede fish passage. See also H7. Construct migration facilities; operate sediment traps; comply with RWQCB Section 401 Certification requirements; have funding available for emergency action. (NLP 8.4.1-1 as refined by permits)

Yes, SWRCB Permit 20808 Conditions #21, 23, 43, and 45;

COE 404 Permit 20364S09 Special Conditions #2 and 3.

LS
VEGETATION AND WILDLIFE  
VW1. Loss of 127 acres of mixed hardwood forest and coast live oak woodland. Acquire rights to preserve adjacent forest and woodland in a 3:1 ratio (at least 380 acres) as wildlife habitat. ( NLP 9.3.1-2) Yes, SWRCB Permit 20808 Conditions #25 and 45. LS
VW2. Loss of 6.3 acres of valley oak woodland Implement Valley Oak Woodland Mitigation Plan at 23-acre site described in NLP EIR. (NLP 9.3.1-3) Yes, SWRCB Permit 20808 Conditions #26 and 45. LS
VW3. Loss of 37 acres of riparian habitat not in COE jurisdiction Implement Riparian/Wetland Mitigation Plan approved by COE. (SEIR E.4.1.1)

Yes, SWRCB Permit 20808 Conditions #28 and 45;

COE 404 Permit 20364S09 Special Condition #4.

LS
VW4. Loss of 2.6 of wetland and 55 acres of surface waters within COE jurisdiction. Implement Riparian/Wetland Mitigation Plan approved by COE; create new 266-acre reservoir. (SEIR E.4.1.1)

Yes, SWRCB Permit 20808 Conditions #28 and 45;

COE 404 Permit 20364S09 Special Condition #4.

LS
VW5. Loss of habitat and displacement of federally threatened California red-legged frog. Implement all reasonable and prudent measures identified in Conference Opinion issued by USFWS; Riparian/Wetland Mitigation Plan design incorporates habitat creation for frogs. (NLP 9.3.1-7b; SEIR E.3.1)

Yes, SWRCB Permit 20808 Conditions #28 and 45;

COE 404 Permit 20364S09 Special Conditions #3 and 5.

LS
VW6. Stress to riparian vegetation and wildlife habitat in drought years due to reduced water table. [Beneficial effects in most years.] Irrigation of affected vegetation in drought years, similar to existing program; continue existing wildlife monitoring program for agency review; implement corrective measures if adverse trends are evident. (NLP 9.3.1-8) Yes, SWRCB Permit 20808 Conditions #30, 31 and 45. PSU
Traffic  
T1. During construction period, increased traffic levels on Highway 1 and Carmel Valley, Cachagua and Tassajara Roads; potential damage to roadways from heavy vehicles. Develop (during final design) and implement Traffic/Transportation Plan as part of comprehensive Construction Management Plan. Elements include hiring coordinators, avoiding peak traffic periods, carpooling, shuttle busses and vans, pilot vehicles, safety plan, inspections, road damage repair and other elements. (NLP 10.3.1-1; SEIR 4.2.3-1 through 4.2.3-3) No SU
Climate/Air Quality    
CA1. During construction period, increased regional air pollutant emissions from vehicles and equipment, smoke from burning, and fugitive dust. Develop (during final design) and implement Construction Emission Management Plan as part of comprehensive Construction Management Plan. Elements include trip reduction (see T1), vehicle inspection and maintenance, reduced idling; alternative clearing methods, timber harvest, onsite chipping, burn permits; dust abatement officer, equipment cleaning, wet suppression techniques, and other elements. (NLP 11.3.1-1 through 11.3.1-3; SEIR 5.2.2-1) No SU
Noise  
N1. During construction period, noise levels in the project vicinity would be increased due to construction traffic and activities in the staging area. Develop (during final design) and implement Noise Reduction Plan as part of comprehensive Construction Management Plan. Elements include trip reduction (see T1), restrictions on timing of activities, advisories to nearby residents, mufflers and other sound control techniques, home retrofit program, and other elements. (NLP 12.3.1-1; SEIR 6.2.2-1 and 6.2.2-2) No SU
Visual Quality  
V1. Construction activities will alter existing visual conditions in the project area and result in more nighttime light; the new dam will permanently alter the viewshed in the project vicinity. For construction impacts, develop (during final design) and implement Visual Quality Plan as part of comprehensive Construction Management Plan. Elements include focused lighting, minimize nighttime work, vegetation buffer zone. Long-term efforts include landscaping to shield public views, treatments to dam face, and other elements. (NLP 13.3.1-1 and 13.3.1-2; SEIR 9.2.2-1and 9.2.2-2) No SU
Cultural Resources  
CR1. Loss, damage or disturbance of Esselen cultural properties (archaeological sites) in project area (NHPA Criterion D: potential to contribute information) Implement Programmatic Agreement pursuant to NHPA Section 106; develop umbrella Historic Property Management Plan for sites in this class, and individual treatment plans for each eligible site to be approved by PA signatories. SEIR recommends focus on research design, data recovery, evaluation; avoid and minimize construction impacts as feasible (SEIR 7.2.3-1 through 7.2.3-3).

Yes, SWRCB Permit 20808 Conditions #45-53;

COE 404 Permit 20364S09 Special Condition #1.

Specific measures finalized via Section 106 process.

LS in general
CR2. Loss, damage or disturbance of Esselen cultural properties (traditional cultural properties) or setting for properties in project area (NHPA Criterion A: contributes to broad pattern of history; TCP importance to culture of a people) Implement Programmatic Agreement pursuant to NHPA Section 106; develop umbrella Historic Property Management Plan for sites in this class, and individual treatment plans for each eligible site to be approved by PA signatories. SEIR recommends design changes and construction exclusion areas as feasible to avoid and minimize construction impacts; funding cultural center and other educational efforts to compensate for unavoidable loss; active participation of Esselen as resource specialists during construction; long-term Esselen access to area for traditional plant gathering, dances, prayer and other cultural activities (SEIR 7.2.3-4 and 7.2.3-5)

Yes, SWRCB Permit 20808 Conditions #45-53;

COE 404 Permit 20364S09 Special Condition #1.

Specific measures finalized via Section 106 process.

LS in some cases, SU in others (see SEIR Table 7-3 for detail)
Public Health and Safety  
PH1. Increased risk to worker and public safety during construction. Develop (during final design) and implement Health and Safety Plan as part of comprehensive Construction Management Plan. Elements include hiring safety officer, enforcement of safety plan for workers, vehicles and equipment, fire preparedness and coordination with fire agencies, detailed fire response plan, comply with all safety codes and practices, coordination with community for emergency planning, and other elements. (NLP 15.3.1-1 as amended by 1995 Addendum-2.) No LS
PH2. Catastrophic failure of dam could result in property damage and possible injury and loss of life. Design , construction and operation of dam must comply with state standards and be approved and permitted by state dam safety agency. Perform dam failure analysis for worst case scenario to predict potential impact, then develop Emergency Action Plan for evacuation. (NLP 15.3.1-3.) Yes, SWRCB Permit 20808 Condition #18 LS
PH3. Increased flows (and thus vegetation) due to project operation could result in channel narrowing downstream, and increase extent of 100-year floodplain See H2. Carry out approved 20-year monitoring plan for changes in channel capacity and riparian vegetation growth. If adverse trend observed, implement agency-approved corrective measures such as selective channel clearing and sediment removal. (NLP 15.3.1-2.) Yes, SWRCB Permit 20808, Condition #22 and 45; COE 404 Permit 20364S09 Special Condition #3 LS
Land Use, Planning, Recreation  
L1. Affect to 23 acres of existing Ventana Wilderness Exchange of over 140 acres of similar quality habitat adjacent to Wilderness boundary. U.S. Forest Service "directed" to make this exchange if project approved. (NLP 17.3.1-1) Land exchange required by act of Congress (Public Law 101-539) LS
L2. Recreation at Cachagua Community Center and park, and nearby residences affected by construction traffic, noise, dust See mitigation measures for traffic, noise and climate/air quality No SU
L3. Inundation of portions of Carmel River Trail (public access route through private land to Ventana Wilderness); restrictions on trail use during construction Replace hiking trail by permanent unpaved access road to fish screening facility. Shuttle service during construction. (NLP 17.3.1 through 17.3.1-3; SEIR F3 and F4) No LS
Growth Inducement  
G1. Project could indirectly result in release of estimated 799 af of metered sales for new connections and remodels by MPWMD, contributing to adverse regional traffic and air quality impacts Consider phasing release of water for growth consistent with regional air quality management plan and with traffic infrastructure. Traffic and air quality measures are beyond authority of MPWMD. (NLP 19.0; SEIR 10.4.1) Change in project scope requires regulatory approvals. No PSU


Notes: SU = significant and unavoidable; PS = potentially significant; PSU = potentially significant and unavoidable; LS = less than significant.

"Drought years" in this table refer to dry, critically dry or severe years (25%, 12.5% or 5% of the time, respectively) as defined in CVSIM computer model.