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El Cerro Del Aripo & Pico Escondido Exploration

Scheduled Date: Friday 21st September, 2018

Mountains always bewilder hikers and to conquer the summit of a mountain means a lot to a hiker. Situated between El Cerro Del Aripo and Mt Chagaramal in Aripo there is a hidden peak called Pico Escondido. The questions are 1. Does Pico Escondido qualify to be a separate mountain or is it part of the El Cerro Ridge? 2. Is it higher than Mt El Tucuche the 2nd tallest peak? If the information proves to be true it would mean that the information published in the 1935 Lands and Survey handbook needs to be updated.  It would also mean that the information taught in our geography books need to be corrected. On Saturday 29th September 2018  to celebrate his 76thbirthday Glenn Wilkes along with the Fitness Walkers Group climb the two peaks to survey the landscape and answer the questions. Assembly: 630 am Corner of Omeara Road and Churchill Roosevelt Highway Arima. For details contact Michael 7193368, Jamal 7611889 or Marcia 4902421

Glenn Wilkes distinguished Land Surveyor for over 50 years give an account of his findings

The contours and the search.

Contours are “equal height” lines on a map, that help the map-reader to visualise the topography. Ideally, each contour would have the height written on it, but to avoid cluttering the map, the values are only written intermittently. You have to figure out the rest based on how many contour lines there are between the ones that have values (interpolation).  Actually, you often have to extrapolate, using the contour interval.

El Pico Escondido

Since the 1930’s when the Land Surveyors’ Handbook published data for trigonometrical stations, many of which were on mountain-tops, the highest stations were El Cerro del Aripo at 3,085 feet, and El Tucuche at 3,072 feet. The method used then was “trigonometrical levelling”, where heights are calculated from measured vertical angles.                                                                                                                                                                   On the 1/25,000 topo map sheet #23, there is an insignificant-looking contour on a mountaintop south of El Cerro del Aripo. Counting up from the last value of 2,650, you find that it’s the 3,050 contours. The absence of a 3,100-foot contour means that the area within the 3,050-foot contour is above 3,050 feet but less than 3,100 feet, just like both El Cerro and El Tucuche. It was about 50 years ago that I noticed this, but in those days, long before GPS, the only easy way to calculate such an inaccessible peak was with an altimeter (a height-graduated barometer), which was not very precise. So the peak remained for me just an unresolved mystery. I never went searching for it, and I didn’t give it a name. And then five years ago, a UWI group of surveyors set out to re-measure the heights of Cerro del Aripo and El Tucuche, in order to resolve which was really the higher peak. One reason for the uncertainty was the fact that while El Tucuche had been remeasured when it was included in the DOS survey of the 1960’s, Cerro had not, and had retained its 1930’s height. Implied in their mission statement “Is Cerro del Aripo really higher than El Tucuche?” was that there were no other contenders for the tallest mountain in Trinidad. The UWI group did their (improved) measurements, confirming that Cerro was higher. But their exercise had reawakened my interest, and I decided that the time had come for me to go look for my hidden peak, which I now christened “El Pico Escondido”.

Our initial search involved three of us, Carl James of Brasso Seco, Chris Kelshall and I overnighting at El Cerro del Aripo. My original plan was to run a survey traverse from Cerro to Pico, and I took up my survey instrument. As it turned out the intervening bush was too much and the idea was abandoned. Dan Jaggernauth had joined us on the first day, and after some effort, we made it halfway to the peak. The following day, Carl, Chris Kelshall and I made it to what we estimated was the highest point, where we put a survey “iron”. The only measurement possible was with a hand-held GPS, which confirmed that it was a peak that could rival the “big two”, but not accurate enough to rank the three. It was time to get a more accurate measurement.

On our next trip to Pico, Winston Mohammed and his crew from Geometrics accompanied us, and took accurate GPS measurements at both Cerro and Pico, using the same mark there that we had previously established. So we now had accurate GPS readings for survey marks at El Cerro and El Tucuche (UWI), and one for our “selected” high point on Pico (Geometrics). The race was on!

El Cerro del Aripo – (Trigonometrical station #86)  elevation 3086.3 feet

El Tucuche –  (Trigonometrical station #20A)  elevation 3075.2 feet

El Pico Escondido – (“selected” high point marked with an iron) elevation 3073.8 feet

At this stage, it was obvious that El Cerro was a clear winner, but the second place was so close, that there was a possibility that neither of the locations measured at those peaks was in fact at the “tip-top”, and the order could therefore change. Enter LIDAR (Light detection and ranging).                           I found out that Lands & Surveys had comprehensive LIDAR mapping for Trinidad and Tobago, which though done from the air like the aerial photography, is not impeded by the tree cover, and accurate ground heights are obtained. This would, therefore, solve all the uncertainties. Unfortunately, at this time there is a gap in the Lidar coverage at El Tucuche, so we still only have the GPS height there for the Trigonometrical station.

El Cerro del Aripo – (Lidar highest point, south-east of station)  elevation 3087.6 feet

El Cerro del Aripo – (Trigonometrical station #86) elevation 3086.3 feet

El Pico Escondido – (Lidar highest point north of “selected” high point) elevation 3077.0 feet

El Pico Escondido – (“selected” high point marked with an iron) elevation 3073.8 feet

El Tucuche –  (Trigonometrical station #20A)  elevation 3075.2 feet

*There is, therefore, the possibility that like El Cerro del Aripo, El Tucuche does have a higher point than the Trigonometrical station that the Lidar will detect and height.

Finally, there is the question of whether El Pico Escondido would qualify as a distinct peak, rather than an extension of the Cerro ridge. Chris Kelshall used the recognised criteria (distance and intervening drop in height) to confirm that it is.

Glenn Wilkes                                                                                                                                                                          21-09-2018

El Cerro Del Aripo 

 email: islandhikers@gmail.com

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