Imperial County Airport (IPL)

Aeronautical and Airport Land Use Compatibility Study

Study Overview Michael Baker International, Inc., was tasked by the City of El Centro, California to evaluate the proposed re-zoning of four vacant parcels within the vicinity of Imperial County Airport (IPL). As shown in the graphics throughout this study, the parcels are identified by Imperial County as Assessor’s Parcel Numbers 044-620-049, 044-620-050, 044-620-051, and 044- 620-053. The parcels are located at the northwest and southwest corners of Cruickshank Drive and 8th Street and are currently zoned as Residential Airport Zone (RAP) and fall within the B2 Zone (Extended Approach/Departure Zone) of the 1996 IPL Land Use Compatibility Plan and Map. Table 1 summarizes the existing and proposed characteristics of the four parcels. Since the California Department of Transportation (Caltrans) last updated the California Airport Land Use Planning Handbook, the B2 Zone is no longer defined in the same manner and some zones around runways are also defined differently for Airport Land Use Compatibility Plans (ALUCPs). Therefore, it was necessary to review existing activity data and conditions at IPL in comparison to updated Caltrans guidance to determine if the proposed parcel re-zonings would produce incompatible land uses and/or airspace impacts.

Table 1 Existing and Proposed Parcel Characteristics Zoning Land Use Parcel # Acreage Existing Proposed Existing Proposed 044-620-049 2.08 RAP CG R-R GC 044-620-050 1.05 RAP CG R-R GC 044-620-051 17.23 RAP CG R-R GC 044-620-053 21.79 RAP ML R-R GI Source: Michael Baker International, Inc. and City of El Centro, California. RAP – Residential Airport Zone CG – Commercial General ML – Light Manufacturing R-R – Rural Residential GC – General Commercial GI – General Industrial

Airport Land Use Compatibility Plan (ALUCP) Update As mentioned, Caltrans last updated the California Airport Land Use Planning Handbook in 2011, while the associated ALUCP zones around IPL were adopted in 1996 (updated in 2004) and represent Imperial County’s official ALUCP at this time (refer to Figure 1). The ALUCP zones are a function of the runway length, the type of activity the airport experiences, the precision of the approaches to the runway ends, the traffic patterns around the runways, and the category of the airport (general aviation, commercial, military, etc.). Caltrans also allows some subjective judgement to be applied in the determination of the sizes and shapes of the surfaces surrounding each runway, which are based on unique circumstances and/or operating procedures associated with the runway.

October 27, 2016 1 Imperial County Airport (IPL)

Figure 1 1996 IPL Compatibility Map

Source: Imperial County, California.

October 27, 2016 2 Imperial County Airport (IPL)

Imperial County Airport is included in the Federal Aviation Administration’s (FAA’s) National Plan of Integrated Airport Systems (NPIAS) and is therefore eligible to receive Airport Improvement Program (AIP) grants for eligible projects and studies. IPL is identified as a Regional Commercial Service Airport in the NPIAS and is also a Federal Aviation Regulations (FAR) Part 139 that is certificated to accommodate scheduled small air carrier aircraft with 10 to 30 seats. The airport receives financial subsidies from the U.S. Department of Transportation (USDOT) to provide airline service under the Essential Air Service (EAS) program, which is a program that is intended to assist small communities with providing access to the national aviation system. Airline service at IPL has historically been conducted using medium-sized turboprop aircraft (e.g., nine passenger Cessna 208 Grand Caravans). The purpose bringing this up is because the size of the shapes in the ALUCP differ between general aviation and commercial service airports (refer to sample graphics in Table 2). Because of the nature of the activity at IPL, types of runway approaches, and physical characteristics of the airport, it may be appropriate to identify Runway 14-32 as a general aviation runway as part of an ALUCP. Note that this effort was conducted to determine if Imperial County’s ALUCP was consistent with today’s guidelines, but does not constitute an ALUCP update or policy change. Consequently, the information presented in this study is provided to compare the development restrictions between the existing 1996 ALUCP for IPL to what the current development restrictions might look like under today’s Caltrans regulations. The following assumptions went into the development of the potential 2016 ALUCP in Figure 2:

1. Based on the safety zones for a Medium General Aviation Runway with modifications to illustrate the applicable FAA criteria for IPL. 2. All runway approaches at IPL are currently visual. 3. The runways accommodate regular use by aircraft with maximum certificated takeoff weights of more than 12,500 pounds. Regular use is defined as 500 or more annual operations. 4. In Zone 1, the Runway Protection Zone (RPZ) dimensions are based on a Runway Design Code (RDC) of B-II. 5. The following traffic patterns apply to IPL: Runway 14 (left hand), Runway 32 (right hand), Runway 8 (left hand), Runway 26 (right hand). 6. No future runway extensions or instrument approaches were considered.

The potential ALUCP in Figure 2 has different zone names and shapes than the 1996 one. Based on the 1996 map, the proposed parcel re-zonings are located in the B2 Zone (Extended Approach/Departure Zone), whereas current Caltrans guidance may suggest that the parcels are located in a combination of Zone 5 (Outer Approach/ Departure Zone) and Zone 6 (Traffic Pattern Zone). A summary of the development requirements within the 1996 and current zones is summarized in Table 3 for the four parcels. As shown, current Caltrans ALUCP requirements may actually be less restrictive for the proposed developments on those parcels. For example, the allowable uses, accident risk levels, and maximum densities may currently be less restrictive today than in 1996, and the proposed re-zonings may allow for the development of land uses that are more appropriate with current Caltrans. Therefore, this document should be viewed as a talking point between the City of El Centro and Imperial County regarding any proposed developments within the vicinity of the airport.

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Table 2 Example General Aviation vs. Large Air Carrier Runway ALUCP Medium General Aviation Runway Large Air Carrier Runway

Source: Caltrans 2011 California Airport Lan Use Planning Handbook.

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Legend N Zone 1: Runway Protection Zone Zone 2: Inner Approach / Departure Zone Zone 3: Inner Turning Zone Zone 4: Outer Approach / Departure Zone Zone 5: Sideline Zone Zone 6: Traffic Pattern Zone Parcels Imperial Avenue

West Worthington Road

14 End El. -55.1' (14 - Left Hand)

Airport Road

26 End El. -55.0' 32 End El. -53.9' 8 End El. -55.1' (32 - Right Hand) (8 - Left Hand) (26 - Right Hand)

West Aten Road 8th Street La Brucherie Road 044-620-053 (ML)

Cruickshank Drive 044-620-050 (CG) 0 2,000' 4,000'

044-620-049 (CG) 044-620-051 (CG) Scale: 1" = 2,000'

Figure 2 Potential 2016 ALUCP (Runway 14-32) Imperial County Airport (IPL)

Table 3 Comparison of 1996 and Current Caltrans ACULP Requirements Zoning Zoning Permitted Maximum Urban Densities (Per Acre) Required Open Land Parcel # Acreage Caltrans Zone Risk Existing Proposed Existing Proposed Residential Units Other People Percentage Actual (Acre) 044-620-049 2.08 RAP CG 1996 B2 Zone Not Normally Not Normally Significant 1 100 30% 0.62 044-620-049 2.08 RAP CG Current Zone 4 Limit Normally Moderate Per Comparable Surrounding 150-200 Per Code TBD 044-620-049 2.08 RAP CG Current Zone 6 Yes Yes Low No Limit No Limit Per Code TBD 044-620-050 1.05 RAP CG 1996 B2 Zone Not Normally Not Normally Significant 1 100 30% 0.32 044-620-050 1.05 RAP CG Current Zone 4 Limit Normally Moderate Per Comparable Surrounding 150-200 Per Code TBD 044-620-050 1.05 RAP CG Current Zone 6 Yes Yes Low No Limit No Limit Per Code TBD 044-620-051 17.23 RAP CG 1996 B2 Zone Not Normally Not Normally Significant 1 100 30% 5.17 044-620-051 17.23 RAP CG Current Zone 4 Limit Normally Moderate Per Comparable Surrounding 150-200 Per Code TBD 044-620-051 17.23 RAP CG Current Zone 6 Yes Yes Low No Limit No Limit Per Code TBD 044-620-053 21.79 RAP ML 1996 B2 Zone Not Normally Normally Significant 1 100 30% 6.54 044-620-053 21.79 RAP ML Current Zone 4 Limit Normally Moderate Per Comparable Surrounding 150-200 Per Code TBD 044-620-053 21.79 RAP ML Current Zone 6 Yes Yes Low No Limit No Limit Per Code TBD Sources: Michael Baker International Inc, Caltrans 2011 California Airport Land Use Planning Handbook, and 1996 IPL Compatibility Map. RAP – Residential Airport Zone CG – Commercial General ML – Light Manufacturing

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Airspace Considerations Because the proposed parcel re-zonings are located within 20,000 feet of IPL, they may be subject to FAA airspace review prior to development, which must be submitted through the FAA’s Obstruction Evaluation/Airport Airspace Analysis (OE/AAA) portal. Figure 3 illustrates the strictest approach and departure surfaces over the four parcels. The Runway 32 approach surface extends out beginning 200 feet from Runway 32. It starts at the Runway 32 end elevation of -53.9 feet Above Mean Sea Level (AMSL) and extends up at a rate of one foot vertical for every 20 feet horizontal. The Runway 14 departure surface begins at the Runway 32 end elevation and extends up at a rate of one foot vertical for every 20 feet horizontal. Table 4 illustrates the allowable AMSL at each point along the parcels, as well as allowable Above Ground Level (AGL) elevation above the Runway 32 end elevation. This does not take into account for the local zoning requirements which stipulate that the maximum building height is 35 feet within an RAP zone, 45 feet within an ML zone, and 65 feet within a CG zone (per Chapter 29 of the Code of Ordinances of the City of El Centro). The table also shows the AMSL elevation at each point that would be subject to FAA airspace review (i.e., how high a structure could be constructed at each point before it would be subject to FAA airspace review). This should aid the city, county, and developer in determining appropriate heights and permitting requirements for any proposed structures on those parcels.

Table 4 Maximum Allowable Elevations 100:1 Surface (for FAA 20:1 Approach Surface 40:1 Departure Surface Parcel # Point Airspace Evaluation) AMSL AGL AMSL AGL AMSL AGL 044-620-049 1 96.1 150.0 96.1 150.0 10.9 64.8 044-620-049 2 96.1 150.0 96.1 150.0 17.3 71.2 044-620-049 3 96.1 150.0 96.1 150.0 15.7 69.6 044-620-050 4 96.1 150.0 88.7 142.6 3.2 57.1 044-620-050 5 96.1 150.0 92.2 146.1 4.5 58.4 044-620-050 6 96.1 150.0 96.1 150.0 6.2 60.1 044-620-050 7 96.1 150.0 94.4 148.3 5.4 59.3 044-620-051 8 96.1 150.0 93.1 147.0 4.9 58.8 044-620-051 9 96.1 150.0 96.1 150.0 8.0 61.9 044-620-051 10 96.1 150.0 96.1 150.0 18.8 72.7 044-620-053 11 96.1 150.0 67.3 121.2 -5.4 48.5 044-620-053 12 96.1 150.0 80.9 134.8 0.0 53.9 044-620-053 13 96.1 150.0 96.1 150.0 6.8 60.7 044-620-053 14 96.1 150.0 84.8 138.7 1.6 55.5 Source: Michael Baker International, Inc., 2016. Notes: The end elevation of Runway 32 is -53.9 feet Above Mean Sea Level (AMSL). The allowable AMSL is the maximum allowable height within each surface. The allowable Above Ground Level (AGL) is the allowable height above the runway end elevation. This table does not take into account local zoning requirements.

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Findings According to the California Airport Land Use Planning Handbook, “The publication of the 2011 Handbook does not trigger the need to update a previously adopted ALUCP. However, Airport Land Use Commissions (ALUCs) are well served to consider the adequacy of their adopted ALUCPs with regards to: statutory changes since the last ALUCP update, changes in current or forecasted operations at the airport(s) covered by the ALUCP, and changes in development patterns or land use plans in the vicinity of the airport(s) covered by the ALUCP.” This analysis has shown that the proposed rezoning of the parcels from RAP to ML and CG would allow for the construction of land uses that are more compatible based on current Caltrans regulations (e.g., commercial and light manufacturing are more compatible land uses than residential). The following definition of an RAP zone is from Chapter 29 of the Code of Ordinances of the City of El Centro:

Residential Airport Zone (RAP)

RAP residential airport zone. This zone is intended to provide consistency with the airport comprehensive land use plan by allowing for the development of residential uses within areas designated as "extended approach/departure zone" under the Imperial County Airport Land Use Compatibility Plan where risk factors have been identified resulting in the need for restricting density. This zone allows development of a single-family home (or mobile home on a permanent foundation) at a maximum density of one (1) dwelling unit per acre. Subject to article V, division 6 conditional use permit, densities allowed under the R1 zone shall be allowed so long as development is clustered in a manner that the average density within those portions of the site designated "extended approach/departure zone" does not exceed one (1) dwelling unit per acre subject to the provisions of article V, division 6 conditional use permit.

The 1996 IPL Land Use Compatibility Plan indicates that the majority of residential development is incompatible within a B2 zone, with the exception of some low density residential developments that are potentially compatible with restrictions. Conversely, the 1996 plan indicates that many types of industrial and commercial developments are potentially compatible with restrictions within a B2 zone. Therefore, the proposed zoning changes would also support more compatible land uses within the B2 zone from the 1996 plan. Based on the information in the 2011 California Airport Land Use Planning Handbook, the associated zones and policies at IPL would likely be less restrictive for light manufacturing and commercial development (as shown in Figure 2).

These factors should be a consideration as part of the development review process by the Imperial County ALUC. It is anticipated that any development on the four parcels would not exceed height standards as set forth in Chapter 29 of the Code of Ordinances of the City of El Centro for ML and CG zones, which would not produce any obstructions to the existing approach and departure surfaces to the south of the Runway 32 end. Therefore, the proposed zoning changes should be viewed as acceptable changes, so long as they are compatible with surrounding land uses.

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N

West Aten Road

Parcel Line (Typ.) 12

8th Street 32 End 13 El. -53.9' 9

Extended Runway 044-620-053 Centerline (Typ.)

10 11 8 044-620-051 5 6 2 Imperial Avenue 20:1 Approach Surface 1 14 4 7 044-620-049 044-620-050

3

40:1 Departure Surface

Cruickshank Drive

0 500' 1,000'

Scale: 1" = 500'

Figure 3 FAA Airspace Review Imperial County Airport (IPL)

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