Attach_3-GFD__3_-_Percolation_Tests.pdf

Kennedy/Jenks Consultants

© Kennedy/Jenks Consultants, Inc.

11 April 2018

Memorandum

To: National Park Service (NPS) Haleakala National Park

From: Kennedy/Jenks Consultants (K/J)

Subject: Trip Report – Rehabilitate HVC Wastewater System Conversion from R-1 to IWS (Phase I) - PMIS #238503B (Phase II) - PMIS #238503C Haleakala National Park K/J 1567002*19

K/J visited Haleakala on March 12 and 13, 2018 to field check the topographic survey and conduct percolation tests for the sizing of the leachfield.

Site visit attendees:

March 12, 2018 Rusty Waltrip, NPS Rachel Hodara, NPS Jon Honda, K/J Alicia Nakano, K/J

March 13, 2018 Rusty Waltrip, NPS Jon Honda, K/J Alicia Nakano, K/J

This trip report provides documentation of observations of existing water, wastewater and drainage system, and incorporates information shared by NPS . Construction of PMIS #225505 was ongoing.

Existing Potable Water System

The existing potable water system is made up of a 5,000 gallon underground storage tank and booster pump system, which supplies potable water to the drinking fountain and sinks in the Comfort Station and Visitor Center. Potable water usage was reported by NPS to be approximately 2,200 gallons every two weeks, or 160 gallons per day.

At the time of our site visit, K/J observed potable water being delivered by a NPS water truck.

NPS indicated that the onsite potable water tank is filled approximately every 2 weeks, either by NPS or an independent contractor.

Memorandum NPS Haleakala 1567002.19

Existing Drainage System

Storm water runoff is collected and stored for toilet flushing water at the Comfort Station and Visitor’s Center facilities. Figure 1A and 1B show the existing drainage patterns observed by K/J.

Storm water is collected by Grate Inlet #2, located on the west side of Crater Road, approximately 190 feet uphill of the Visitor Center parking lot, see Photo 1. The steel frame was measured to be 41” x 24”. Grate Inlet #2 has an invert 4’ below ground surface, an 8” PVC outlet, and an 18” PVC overflow. The invert of the overflow pipe was approximately at the top of the outlet pipe. K/J does not have as-built information of the inlet and drain line. The drainage area appears to include Crater Road and areas uphill to the crater rim, including portions of the Pu’ua’ula and Paka’ao’ao hills.

NPS staff reported that Grate Inlet #2 overflows during large storm events. This report is consistent with the observed erosion behind the asphalt curb.

K/J also observed evidence of sediment runoff from surrounding hills. The 18” overflow pipe was observed to be approximately half full of sediment, as shown in Photo 2. K/J observed a concrete block in the storm drain inlet in front of the 8” outlet pipe. NPS said they installed the concrete block in order to reduce the amount of sediment flowing into the outlet pipe. NPS staff report that they clean the storm drains after large storm events.

Photo 1 – Grate Inlet #2 looking south

JonHonda Snapshot

JonHonda Snapshot

JonHonda Text Box EXCERPT FROM UNITED STATES GEOLOGICAL SURVEY. KILOHANA, HI 1991 NIMA 5719 II NW-SERIES W833 MAP

JonHonda Callout

APPROXIMATE LOCATION OF GRATE INLET #2

JonHonda Callout

RUNOFF FROM HILLSIDE FLOWS ONTO ROAD AND IS CONVEYED DOWNHILL

JonHonda Polygon

JonHonda Callout

BEND IN ROAD WHERE SIGNIFICANT FLOWS MAY LEAVE ROADWAY

JonHonda Arrow

JonHonda Arrow

JonHonda Arrow

JonHonda Arrow

AliciaNakano Text Box

FIGURE 1A DRAINAGE AREAS

AliciaNakano Callout

SEE FIGURE 1B FOR DRAINAGE IN THIS AREA

NPS Haleakala 1567002.19

Photo 2 – Overflow pipe from Grate Inlet #2 looking east

Storm water from Grate Inlet #2 flows north to a concrete drain manhole, DMH 1, located at the southwest side of the Crater Road and visitor center parking lot intersection, shown in Photo 3.

DMH 1 has a 5’6” outside diameter, and invert approximately 3 feet from grade. The 8” PVC influent pipe was observed to be approximately half full of sediment as shown in Photo 4.

NPS Haleakala 1567002.19

Photo 3 – Drain Manhole (DMH 1) looking northwest

Photo 4 – Drain Manhole (DMH 1) looking east

NPS Haleakala 1567002.19

© Kennedy/Jenks Consultants, Inc.

NPS staff reported that during large rain events, DMH 1 overflows. Erosion of the ground near the manhole was observed, as seen in Photo 5.

Photo 5 – Erosion near Drain Manhole (DMH 1) looking southwest

From DMH 1, an 8” PVC line conveys stormwater northeast to Grate Inlet #1. NPS suspects there is a “hump” in the line because water has been observed to flow back into DMH 1 when they clean sediment from DMH 1. The survey show that the discharge invert elevation is approximately the same elevation as the inlet invert. K/J does not have as-built information of the manhole and drain line.

Grate Inlet #1 is located adjacent (north side) to the entrance to the Visitor Center parking lot.

Grate Inlet #1 is a 48” x 48” (inside dimension) concrete storm drain with a grate inlet. The grate frame was measured to be approximately 50” x 50” with an 8” thick steel angle supporting fabricated hinged grates, shown in Photo 6. The invert of the grate inlet structure was measured about 48” below grade, with a 8” PVC inlet pipe was measured to be about 41” below grade, and 10” PVC outlet pipe about 41” below grade. Grate Inlet #1 collects a portion of runoff from the parking lot and Visitor’s Center. However, runoff from portions of the parking lot, Visitor Center, and Paka’ao’ao hill bypass Grate Inlet #1 and flow west, out of the parking lot.

NPS Haleakala 1567002.19

Photo 6 – Grate Inlet #1 looking northeast

NPS Haleakala 1567002.19

© Kennedy/Jenks Consultants, Inc.

Storm Water Treatment

Storm water from Grate Inlet #1 flows to a concrete vault located on the north side of the visitor center parking lot. Inside the concrete vault are 2 strainers. A 10” ductile iron tee splits the flow into the duty strainers, and combines the flow with a tee on the downstream end before leaving the vault. Flow capacity of the existing strainers have been requested with NPS. See strainer vault in Photo 7.

Photo 7 – Strainer Vault looking south

NPS Haleakala 1567002.19

Storm Water Storage

NPS indicates that flow from the strainers discharge into the existing 50,000 gallon underground storage tank. NPS staff said that the concrete vault is within the existing underground storage tank. The material of construction of the 50,000 gallon underground storage tank is unknown. The 50,000 gallon underground storage tank has an overflow and daylights at the surface. The 6” ductile iron overflow is shown in Photo

8. K/J does not have as-built information of the vault and tank.

Photo 8 – Overflow Pipe looking South

Strained storm water from the 50,000 gallon underground storage tank is pumped by a submersible pump (located inside the tank) to 2 – 25,000 gallon underground storage tanks. The submersible pump, Storm Water Pump #1, is rated for 35 gallons per minute with a motor of 1 horsepower. The 3” PVC discharge line is routed vertically between the two strainers and into a separate vault that contains gate valves.

NPS Haleakala 1567002.19

Photo 9 – Valve vault upstream of 2 – 25,000 gallon tanks

The network of pipe and valve in this vault provide NPS manual control of which 25,000 gallon tank is used. The material of construction of the 25,000 gallon underground storage tanks are unknown.

NPS staff report that the existing underground “Sidewalk Tank”, southernmost tank located under the parking lot sidewalk, is leaking and is not currently in use. Instead, strained storm water is pumped into the existing underground “Cinder Tank”, located north of the “Sidewalk Tank”, for storage. K/J does not have as-built information of the tanks.

Strained storm water is pumped (by Storm Water Pump #2, see Photo 10) from the set of 25,000 gallon storage tanks to the Reclaimed Water storage tank through a 1-1/2” PVC pipe.

NPS Haleakala 1567002.19

Photo 10 – Storm Water Pump #2

Per record drawings, the 10,000 gallon Reclaimed Water storage tank is a 10’ diameter fiberglass tank, with an 4” PVC overflow that discharges into the Disposal Manhole, and a 3” PVC outlet.

Storm Water Distribution

From the Reclaimed Water storage tank, strained storm water flows through the outlet to to the 11’ x 13’ x 15’ deep concrete Reclaimed Water Pump Vault (See Photo 11), where duplex pump system and a 275 gallon hydropneumatic tank exists. The pumps are rated at 60 gpm with a motor of 5 horsepower. The hydropneumatic tank maintains the distribution system pressurized for toilet flushing at the Visitor Center and Comfort Station. NPS reported that the pumps turn on to pressurize the hydropnuematic tank at 51 psi, and turn off at 58 psi.

NPS Haleakala 1567002.19

Photo 11 –Reclaimed Water Pump Vault looking south

An existing reclaimed water meter on the discharge pipe from the Reclaimed Water Storage Tank pumps is located in a water meter box in front of the comfort station. NPS reports that usage records indicate use of 2,200 gallons per day.

Photo 12 –Reclaimed Water Meter

NPS Haleakala 1567002.19

Existing Wastewater System

General

The existing wastewater system is currently providing wastewater treatment utilizing three septic tanks (2 – 10,000 gallon fiberglass tanks in series followed by a third 10,000 gallon fiberglass tank (previously the Recirculation Tank). Disposal of wastewater is achieved utilizing an existing Seepage Pit.

It should be noted that the third tank, previously used as the Rerciruclation tank, is currently being retrofitted with a baffle and a filter on the effluent end to provide more treatment capacity to the system.

The treatment and disposal system is supported by a network of 6” PVC sewer pipes, manholes, cleanouts, and splitter structures for collection and conveyance of wastewater.

The existing wastewater flow can be estimated by adding potable water daily usage to the existing reclaimed water daily usage:

160 gpd + 2,200 gpd = 2,360 gpd

Service

The existing wastewater system serves the Visitor’s Center, Women’s and Men’s restroom buildings. Fixtures were observed as follows:

Women’s Restroom 10 Toilets (Water Saving Flush 1.6 gpf / 1.1 gpf) 4 Faucets (Twist, metering operated)

Men’s Restroom

6 Waterless urinals, including 1 child’s urinal (NPS staff reports that the waterless urinals are clogging so they will be changed to flush type) 2 Toilets (Water Saving Flush 1.6 gpf / 1.1 gpf) 3 Faucets (Twist, metering operated)

Family Restroom (located within Men’s Restroom Building)

1 Toilet (Water Saving Flush 1.6 gpf / 1.1 gpf) 1 Faucet (Twist, metering operated)

Visitor Center (empoloyee use only)

1 Toilet 2 Sinks

NPS Haleakala 1567002.19

Collection, Treatment and Disposal System

Wastewater is collected in a network of 6” PVC sewer pipe and concrete sewer manholes (SMH) and concrete splitter structures. Sewer manholes are used in the system where a change in pipe direction is required for sewer piping, and spiltter structures are used where the system requires distributing the wastewater flow to two locations.

Photo 13 – Splitter #1 (looking west) – designed to distribute wastewater flow to either Septic Tank #1 (left channel) or Septic

Tank #2(right channel, note existing plug.).

NPS Haleakala 1567002.19

Wastewater from SMH# 3 discharges into a tank previously used as a Recirculation Tank. NPS reports that it will retrofit the 10,000 gallon tank and system piping to utilize it as a septic tank, now identfied as Septic Tank #3. NPS staff reports that they are installing a baffle and effluent filter in the existing tank. The effluent pipe from the Septic Tank #3 has been connected to the existing Disposal Manhole.

In the Disposal Manhole, the overflow from Splitter #3 is plugged, and the overflow from the tank previously used as the Reclaimed Water tank will be plugged. The combined effluent from the Disposal Manhole is discharged to the existing injection well.

During the site visit, as part of PMIS #225505, NPS reported the demolition and removal of the following (see Figure 2):

Equipment within Recirculating Tank including effluent filter, pump assembly, float assembly, recirculation valving, and associated Sewer Forcemain

Equipment within Chlorine Contact Tank including pumping system, float controls, appurtenances, electrical systems and components

Splitter #2 concrete structure and contents including turbidimeter, hypochlorite tank, pump, piping/valves, miscellaneous equipment/contents

Splittler #2 associated Duplex Lift Station Recirculating Sand Filter, distribution valve box, and associated piping

Photo 14 –SMH #3 looking east – designed to received treated wastewater from Septic Tank #1 (right channel, note existing plug) and Septic tank #2 (left channel)

AliciaNakano Text Box

FIGURE 2 SYSTEM LAYOUT

NPS Haleakala 1567002.19

© Kennedy/Jenks Consultants, Inc.

Additional Field Work

Percolation Test

Percolation Tests were performed in accordance with Chapter 62 of Title 11, Hawaii Administrative Rules, Wastewater Systems, to obtain data to size the leachfield system.

NPS staff assisted K/J by digging three test holes and providing water for testing. NPS staff reported that area of proposed leachfield was previously a parking lot, but was filled and covered with cinder.

Test pit locations and percolation test data are provided are shown in Appendix A. The percolation rate results are summarized in Table 1. Photos of the test pits are provided following Table 1.

Table 1 – Percolation Test Results

Location Percolation Rate (min/inch)

Pit 1 4.0 Pit 2 10.0 Pit 3 2.5

Photo 15 – Test Pit 1

NPS Haleakala 1567002.19

Photo 16 – Test Pit 2

Photo 17 – Test Pit 3

APPENDIX A

PERCOLATION TEST

AliciaNakano

AliciaNakano Text Box

AliciaNakano

Project Name:

K/J Job Number:

Date/Time:

Test Performed by:

Hole No.:

Diameter of Hole:

Depth to Hole Bottom:

Soil Description:

Weather Condition:

Reading Time Interval Reading (in.) Drop in

No. (min) Initial Final inches

1 2 6 4 2

2 2 6 4 2

3 2 6 4 2

4 2 6 4 2

5 2 5.75 4 1.75

6 2 6 4 2

7 2 6 4 2

8 2 6 4 2

9 2 6 4 2

10 2 6 4 2

11 2 6 4 2

12 2 6 4 2

13 5 6 4 2

14 5 6 5 1

15 5 6 5 1

16 5 6 4 2

17 5 6 5 1

18 5 6 4 2

19 6 6 4.5 1.5

Percolation Rate (final drop interval) 4.0 min/inch

8 inches

31 inches

Brown cinder throughout

Misty, cloudy

Rehabilitate HVC Wastewater System Conversion from R-1 to IWS (Phase I) - PMIS #238503B

1567002*19

March 12, 2018 / 11:00 am

Jon Honda & Alicia Nakano

Standard Forms: Percolation Tests March 2018.xls

K/J Job Number:

Date/Time:

Test Performed by:

Hole No.:

Diameter of Hole:

Depth to Hole Bottom:

Soil Description:

Weather Condition:

Reading Time Interval Reading (in.) Drop in

No. (min) Initial Final inches

1 10 6 4.75 1.25

2 10 4.75 3.5 1.25

3 10 3.5 2.75 0.75

4 10 2.75 2 0.75

5 10 6 4.75 1.25

6 10 4.75 3.5 1.25

7 10 3.5 3 0.5

8 10 3 2 1

Percolation Rate (final drop interval) 10.0 min/inch

32 inches

Top 12" Brown Cinder, middle 12" grayish fine gravel

Bottom layer reddish clay

Misty, cloudy

Rehabilitate HVC Wastewater System Conversion from R-1 to IWS (Phase I) - PMIS #238503B

1567002*19

March 13, 2018 / 9:20pm

Jon Honda & Alicia Nakano

9 inches

K/J Job Number:

Date/Time:

Test Performed by:

Hole No.:

Diameter of Hole:

Depth to Hole Bottom:

Soil Description:

Weather Condition:

Reading Time Interval Reading (in.) Drop in

No. (min) Initial Final inches

1 5 6 4 2

2 5 6 4 2

3 5 6 4 2

4 5 6 4 2

5 5 6 4 2

6 5 6 3 3

7 5 6 3 3

8 5 6 3 3

9 5 6 3 3

10 5 6 4 2

11 5 6 4 2

12 5 6 4 2

Percolation Rate (final drop interval) 2.5 min/inch

36 inches

Top 12" Brown Cinder

Bottom boulders with brown cinder

Misty, cloudy

Rehabilitate HVC Wastewater System Conversion from R-1 to IWS (Phase I) - PMIS #238503B

1567002*19

March 12, 2018 / 2:30pm

Jon Honda & Alicia Nakano

11 inches