5. Answer. Travel was very difficult and unpredictable. Many journeys suffered delays or outright failure because the guides became disoriented and could not decide which way to go. Communication was almost non-existent.
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5. Exhibit A. We established previously that the Mezcalapa-Grijalva was relatively more densely populated in antiquity than the Usumacinta. See the article "Water Fight on the River - Round Three" in this blog.
5. Conclusion A. The more people you encounter along the way as you travel, the less likely you are to get lost. Advantage Usumacinta.
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5. Exhibit B. We established previously that the Mezcalapa-Grijalva has much swifter current than the Usumacinta because its slope gradient is five times higher. See the article "Dividing the Rivers" in this blog.
5. Conclusion B. People traveling along a river course are less likely to get lost if the direction of flow is unambiguous. Faster current makes the direction of flow more obvious. Advantage Usumacinta.
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5. Exhibit C. Sinuosity is a measure of how straight or how crooked a river is. First, the upper Mezcalapa-Grijalva which covers 127 straight line kilometers in 178 river kilometers for a sinuosity of 1.40.
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| Upper Mezcalapa - Grijalva River. |
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| Upper Usumacinta River. |
5. Conclusion C. The more sinuous a river, the more likely people traveling along it will get lost. Advantage Usumacinta.
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5. Exhibit D. We will bisect each river with four 60 kilometer transects set perpendicular to the direction of flow. We will then have Google Earth calculate the elevation profile for each transect and we will determine the relative elevation difference between the river and the highest point within 30 kilometers on either side. This will measure the potential lookout points guides could have used anciently to orient themselves as they traveled along the river. The example below is from the upper Mezcalapa-Grijalva. The red line is the transect. The elevation profile shows a 1,221 meter peak within 30 kilometers of the south bank of the river. It also shows the river at an elevation of 539 meters. 1,221 - 539 = 682 meters of vertical rise. This means that at this spot, there is a potential lookout point 682 meters high within 30 kilometers of the river. Keep in mind that this portion of the river was dammed in 1976 so the water level in Angostura Reservoir is higher than it would have been in Book of Mormon times.
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| Elevation Profile of a 60 kilometer transect bisecting the upper Mezcalapa-Grijalva River. |
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| 8 sample points for 60 kilometer elevation transects. |
Usumacinta Point A: 418 - 102 = 316 meters vertical rise. Point B: 767 - 82 = 685 meters vertical rise. Point C: 426 - 17 = 409 meters vertical rise. Point D: 57 - 5 = 52 meters vertical rise. Average = 366 meters vertical rise.
5. Conclusion D. The higher the surrounding mountain peaks, the easier it will be for travelers to orient themselves as they move along or near a river course. In our small sample, the mountains surrounding the Mezcalapa-Grijalva are 3.76 times higher those surrounding the Usumacinta. Advantage Usumacinta.
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5. Exhibit E. The NASA Earth Observations Terra/MODIS mission mapped the height of forest tree canopies by measuring the signal bounce differential between the tree line and the ground. We have superimposed tree canopy height data on top of our base map of the rivers. White areas are unforested. The darker the green color, the higher the forest canopy. For visual contrast, the river basin boundaries are in yellow. The Mezcalapa-Grijalva flows through country that for the most part is unforested. The Usumacinta, on the other hand, flows through many areas of tall trees in dense forests.
5. Conclusion E. Travelers wandering around under tall forest canopies are much more likely to get lost than people going through more open country with fewer trees. Advantage Usumacinta.
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5. Conclusion. The Mezcalapa-Grijalva cannot be the river Sidon. All the narratives of groups getting lost coming down from Nephi or up from Zarahemla do not make sense in its ecological context. The same stories make perfect sense set in the Usumacinta drainage basin. An episode in Guatemalan history provides an apt referent. In 1695, the Governor of Guatemala, Don Jacinto de Barrios, mounted a large military expedition to engage the Lacandon Indians who had killed a number of Catholic missionaries sent to convert them. Four different armies entered the Usumacinta River basin from four different staging points. The army that came up river from Yucatan disbanded before they achieved their goal. History does not record what happened to the army that went north from Cahabon, Alta Verapaz, but they never reached their destination. The army that went down into the jungles from Huehuetenango did reach the Lacandons after 30 days of hard travel. The fourth group that left from Ocosingo (Chiapas was part of Guatemala during Spanish colonial times) got lost and wandered around for many days before they were finally discovered by members of the Huehuetenango group who had sent out search parties to rescue them. It all sounds very familiar.
5. Running Score. Mezcalapa-Grijalva 0. Usumacinta 5.
5. Conclusion D. The higher the surrounding mountain peaks, the easier it will be for travelers to orient themselves as they move along or near a river course. In our small sample, the mountains surrounding the Mezcalapa-Grijalva are 3.76 times higher those surrounding the Usumacinta. Advantage Usumacinta.
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5. Exhibit E. The NASA Earth Observations Terra/MODIS mission mapped the height of forest tree canopies by measuring the signal bounce differential between the tree line and the ground. We have superimposed tree canopy height data on top of our base map of the rivers. White areas are unforested. The darker the green color, the higher the forest canopy. For visual contrast, the river basin boundaries are in yellow. The Mezcalapa-Grijalva flows through country that for the most part is unforested. The Usumacinta, on the other hand, flows through many areas of tall trees in dense forests.
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| NASA data showing forest canopy heights in the two river basins. |
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5. Conclusion. The Mezcalapa-Grijalva cannot be the river Sidon. All the narratives of groups getting lost coming down from Nephi or up from Zarahemla do not make sense in its ecological context. The same stories make perfect sense set in the Usumacinta drainage basin. An episode in Guatemalan history provides an apt referent. In 1695, the Governor of Guatemala, Don Jacinto de Barrios, mounted a large military expedition to engage the Lacandon Indians who had killed a number of Catholic missionaries sent to convert them. Four different armies entered the Usumacinta River basin from four different staging points. The army that came up river from Yucatan disbanded before they achieved their goal. History does not record what happened to the army that went north from Cahabon, Alta Verapaz, but they never reached their destination. The army that went down into the jungles from Huehuetenango did reach the Lacandons after 30 days of hard travel. The fourth group that left from Ocosingo (Chiapas was part of Guatemala during Spanish colonial times) got lost and wandered around for many days before they were finally discovered by members of the Huehuetenango group who had sent out search parties to rescue them. It all sounds very familiar.
5. Running Score. Mezcalapa-Grijalva 0. Usumacinta 5.
