Waimea Beach Earthcache (no physical container!)
Waimea Beach is known world-wide for its summertime gentle beach fun and its wintertime stupendous waves, making it inarguably one of Oahu’s top ten destinations for surfers, families, and folks who just enjoy good beach vibes. There’s a geologic back story to this beautiful spot which makes it a unique place on the island. You can find other locations somewhat similar to this on Oahu, but none which better illustrates this particular type of beach. Enjoy this learning experience during your visit!
Looking southwest to Waimea Bay Beach Park from Pu'u o Mahuka Heiau State Park,
on the bluff above and to the east of the river and beach. In this image, note how the ocean's
waves are breaking over the beach into the lagoon formed by the beach's barrier.
All photographs are taken by Wesley H Skinner Jr. (NorthWes) Permission is required from the photographer for any use.
To log this earthcache you must learn what makes this beach geologically unique, record several simple general measurements during your visit (no tools needed!),
and post a required photograph from your time here of one particular location
(as well as however many others you’d like to share from your visit to this beautiful place.) Here’s the logging requirements, but you need to read this entire cache listing to grasp the learning intentions.
Waimea Beach Earthcache Learning Questions:
After sending your requested answers in a message to the cache owner, go ahead and log your find with the required photo without waiting for an answer. The cache owner will contact you if your answers need clarification. Failure to comply with these requests means your log will be deleted. If you have mobility issues which keep you from accessing the sand beach, contact the cache owner for alternate instructions.
Please exercise caution here around the ocean waters –
from time to time the ocean overwashes the cache coordinates. If the site is blocked off by lifeguards, simply note that in your log, move to the closest point that’s safe to observe from, and perform the logging requirements to the best of your ability.
Please note your caching visit must be after the publication date of this cache.
The cache owner has a sample ‘found it’ log at the end of this cache description.
Logging Requirements: 7 easy steps...
- Standing at the cache coordinates, observe if the beach is a barrier to the river,
or if it’s been breached through to the ocean. Post this answer in your found-it log and your message to the cache owner.
- Standing at the cache coordinates, estimate the following and report to cache owner:
A) how high are your feet above observed sea level?
B) how high are your feet above the Waimea River water level nearby?
C) how deep would a channel have to be to allow any river water to flow to the ocean?
- Standing at the cache coordinates looking upriver, is the Waimea River visible as...
(between the beach and the highway bridge):
A) a defined river channel with a large field of vegetation in view between the highway and the waterway on the left side of the river channel, or is it
B) a relatively wide lagoon with water covering the vegetation on the left side of the waterway all the way up to the highway?
Report in your message to the cache owner which description is the closest match to what you're seeing today during your visit.
- Standing at the cache coordinates, looking southwest down the beach,
briefly describe how the beach profile appears from here in your own words.
Include a description of the composition of the beach berm,
and the shape of the beach profile in your message to the cache owner.
- Standing at the cache coordinates, take a photo looking upriver, capturing the beach in the foreground as you photograph the appearance of the estuary or river channel to the highway bridge. Post this required photo with your log.
Logs without this required photo will be deleted without prior notice.
- Starting at the cache coordinates, pace the distance to the closest point where the Waimea River waters meet the beach's northeast side. Enter this number of paces on your found-it log as well as messaging it to the cache owner.
- Please practice CITO during your visit. If you have a CITO moment worthy of a photo, include that with your log. Leave this place in better shape than you found it! Additionally - leave a favorite point on your log if your visit here was a rewarding experience - thank you!
Background information to understand what you're seeing here:
What are beaches? A beach is a narrow strip of land separating a body of water from inland areas. They are found along the edge of an ocean, lake, or river. Beaches are often made of sand, tiny grains of rocks and minerals that have been worn down by constant pounding by wind and waves. Beaches are constantly changing. Tides and weather can alter beaches every day, bringing new materials and taking away others.
Every beach has a beach profile. A beach profile describes the landscape of the beach, both above the water and below it. Beaches can be warm, and rich in vegetation such as palm or mangrove trees. Beaches can also be barren desert coastlines. Other beaches are cold and rocky, while beaches in the Arctic and Antarctic are frozen almost all year.
The area above the water, including the intertidal zone, is known as the beach berm. Beach berms can include vegetation, such as trees, shrubs, or grasses. The most familiar characteristic of a beach berm is its type of sand or rock. Beach berms can be sandy (made of eroded bits of material nearby such as rock, coral, lava, or soft soils from nearby rivers), or rocky (made up of flat pebbles called shingles or rounded rocks known as cobbles, or even seemingly solid coral or rock formations), or a mixture of both.
Some beaches, called barrier beaches, protect the mainland from the battering of ocean waves. These beaches may lie at the heads of islands called barrier islands. Many barrier beaches and barrier islands stretch along the Atlantic and Gulf coasts of the United States. These narrow beaches form barriers between the open ocean and protected harbors, lagoons, and sounds.
Waimea Beach is a unique kind of barrier beach, in that it blocks the Waimea River from flowing directly into the Pacific Ocean here on the north shore of Oahu. This beach also separates the north shore landscape from the force and power of the Pacific Ocean along the beach’s spread. Occasionally, the barrier nature of this beach backs up so much water it may form a large river estuary adjacent to the beach. Infrequently, this barrier behavior can cause flooding upstream beyond the highway bridge, threatening homes and historical archeological sites in the Waimea River Falls Park. At times, the lifeguards have allowed locals to dig a narrow channel through the beach to relieve river water height, which leads to a brief ‘river-surfing’ frenzy in the channel. Within hours the ocean’s power is seen as the new channel gets closed in by the on-shore surf transport of sand as well as erosion of the banks of the narrow human-created river channel.
The Waimea River is found in Honolulu County on the island of Oʻahu in the U.S. state of Hawaii. The river's main channel is 1.5 miles long (complete length is 64.4 miles including all tributaries), and has a watershed spanning 13.6 square miles. It is formed by the confluence of the Kamananui stream and the Kaiwikoʻele stream northeast of Haleiwa and flows northwest through the Waimea Valley to the Pacific Ocean at Waimea Bay. The name Waimea translates to "red water." Waimea River has a bayhead barrier beach where it enters Waimea Bay on northern Oahu. At times the river fills the estuary between the highway bridge and the beach, raising in water level height until the beach is breached and the lagoon/river drains out to the bay. Occasional flooding occurs in the lower portions of the river estuary when water rises rapidly (for example, from intense periods of rain) before the beach is breached. The slightly curved pocket beach is about 1500 feet long and 150 feet wide. The width of the beach varies seasonally based on the change in onshore water movement, with the sand from the southwest end moving to the northeast during the winter, and then moving back in the summer. Some sand may also move offshore during the winter. Waimea Beach has a steep foreshore (the area between water and the top or back edge of the beach) in the winter and a flat one during the summer. There is generally one berm formed on the beach, but sometimes two are formed.
Waimea Bay Beach Park is a fee-free site owned by the city and county of Oahu and managed by the Department of Parks and Recreation. Free parking is available onsite (about 70 spaces), but it is often full by 8:30am. You can either patiently loiter in your car in the parking lot while waiting for someone to leave, or you can park across the highway in private lots on the road to the Waimea Falls Valley Park. Some parking is available along the highway as well, but can be challenging for drivers to access when driving small rental cars. Please note: year-round the beach is overseen by the members of the North Shore Lifeguard Association, working for the county parks department. Lifeguards set up the boundary lines and safety markers you’ll see as you walk out on the beach, and patrol the area to manage beach behaviors for the best safety outcome. Heed their warnings and guidance to help make your visit a safe one. They put their life on the line daily protecting you here – honor their service with your compliance.
Two opportunities to enrich your cultural understanding of this area
It is highly recommended to visit the nearby Pu'u o Mahuka Heiau (religious site) State Park, on the bluff to the north of the beach, with a commanding view of the Waimea Beach Park and Waimea River (and a geocache!) Interpretive signs at this Heiau, Oahu's largest, explain the purpose and use of this site. Access the heiau via the road heading up the bluff at the stoplight next to Foodland, north of this beach, and watch for the state park sign and access road on the right at the top of the bluff. Make time to tour the Waimea Falls Valley park (across the highway and up the valley to the south of the beach), to learn the rich pre-contact history of this area, including use of the river and beach. As a Native Hawaiian–owned nonprofit, the mission of the Valley is to “Preserve and perpetuate the human, cultural and natural resources of Waimea for generations through education and stewardship”. The botanical gardens and cultural sites are well worth the visit, as are the farmer’s markets and artist activities often set up there.
Sample Log format: (this is a minimum; post as much information as you'd like to share!)
During my visit to Waimea Beach, I observed that the beach was acting as a barrier to the outflow of Waimea River. It took 36 paces to reach the river’s edge from the cache coordinates. My photo looking towards the bridge from the cache coordinates is attached.
References:
National Geographic Online Resource Library
https://www.nationalgeographic.org/encyclopedia/beach/
Waimea Falls Valley park
https://www.waimeavalley.net/
Wikipedia
https://en.wikipedia.org/wiki/Waimea_River_(Oahu)
Hawaiian Watershed Atlas
https://www.hawaiiwatershedatlas.com/watersheds/oahu/36010.pdf
COASTAL GEOLOGY OF HAWAII; Ralph Moberly, Jr., with sections by Doak C. Cox, Theodore Chamberlain, Floyd W. McCoy, Jr., and J.F. Campbell, November, 1963
All photographs are taken by Wesley H Skinner Jr. (NorthWes)
Permission is required from the photographer for any use.