Arundo Removal Work at Sabino Canyon

On 27th November, 2009 I volunteered for the removal of a species called Arundo donax, also known as Giant Reed or Giant Cane, at the Sabino Canyon. It is an invasive species to various parts of Riparian habitat and has been a threat to the native plants. This plant spreads very quick in response to floods and debris flows. It uses its rhizomes to spread and very easily remove the competing overstorey trees. This plant is one of the fastest growing plants in the world which can grow up to several inches in a day. It grows so readily from its rhizomes that people are suggested not to use the canes as walking stick, which might contribute in spreading the plant.

Photo-1: Suggestions on Arundo

That day, I joined Jim Wasburne, Assistant Adjoint Professor at the Department of Hydrology and Water Resources at University of Arizona. We reached Sabino Canyon at around 7:30 in the morning and started working from around 8am. There were few bundles of Arundo that were cut some time before and were gathered at one place. We first carried those bundles from that site and piled it near the road so that it could be carried easily from there.

Photo-2: Carrying Arundo Bundles

Photo-3: Arundo Piles

Then, Jim with the help of his another friend Michael, started digging out the well spreaded deep roots of Arundo and cut it into pieces.

Photo-4: Digging out Arundo Roots

Photo-5: Cutting Arundo roots

Then we collected those small pieces of shoots and roots in black polythene bags and carried it to the same place as the piled bundles.

Photo-6: Arundo Roots into Plastic Bags

All these shoots and roots are carried by the US Forest Service and destroyed by burning.

Arundo has already affected a beautiful creek environment. It has very less habitat value and uses lots of water. It uses almost four times more water than any native plants and also competes with the natives for water, nutrients and sunlight. Native plants like willow, cottonwood, ash, and mesquite cannot survive within the Arundo cane thicket because Arundo crowds and kills even mature native trees.

Photo-7: Arundo as a Problem

Arundo even affects native arthropods, and thus reduces habitats for species like birds, reptiles and other wildlife which feed on insects. Arundo does not have any horizontal structures, thus does not support birds or their nests. As the plant is perfectly vertical, it lowers the shade structures in the creek and thus warms the water as well as the micro-climate.

Photo-8: Arundo as a Problem

Hence, to get rid of the Giant Cane, the US Forest Service has been organising an integrated method involving both mechanical (cutting and digging) and chemical (herbicide) processes. A liquid herbicide named Rodeo (glyphosate) is applied on the plant shoots. This herbicide cannot be transferred to human or wildlife when dry.

The plant grows so fast that we could see new sprouts in some places where recently the roots were cut off.

Photo-9: New Sprout from the Roots

If anybody wants to join this work, public volunteer days are being organised for Sabino Canyon Arundo Removal from October, 2009 to March, 2010 on every first Sunday of the month. Interested individuals can send an email to tucson.arundo@gmail.com

Photo-10: Information for Volunteers

More information about this work can be obtained from this site. The video in the link provided is quite informative.

I would like to thank Jim for this opportunity. It was a wonderful experience. And since Sabino Canyon is a good hiking spot, we could also find many people interested for the work.

@ Santa Rita Experimental Range

On 20th November 2009, I had a chance to visit Santa Rita Experimental Range. It was a short visit just to have a general idea about the area. I saw the set ups for measuring the meteorological parameter like rainfall and hydrological parameter like sedimentation, which are worth mentioning here.

The rain gauge was used to measure rainfall in the area. It was present in all the watersheds in the area. Rain gauge was a simple set up of cylindrical jar-type structure, that collects rain water and measures. There was a solar panel beside the set up that provide energy. Data were digitally being recorded from this set up.

Photo-1: Rain Gauge

To measure the sedimentation rate, a metallic curvature was formed on the water-way. During the flow season, when water flows through the metallic section, sediments pass through the holes in the metal and pass to a pipe in the lower part through which it gets deposited in a tank. Data from here is also digitally recorded.

Photo-2: Flume

Photo-3: Metallic Tank where sediment is sampled

On the route of water - flow, there were small blocks of netted rocks acting as gabion wall that reduced the water velocity and contributed in sediment deposition.

Photo-4 a: Netted Rocks

Photo-4 b: Netted Rocks

Gravity effects on water table - USGS

It was on 13th November, 2009 when I joined my friend Brandon Forbes from USGS for the second time in his survey to measure acceleration due to gravity in different places around Tucson.

We did that survey for four different places that day. The water well within the vicinity of El Dorado Hills, Town Homes at Speedway and Caribe was the hub for east Tucson relative to which gravity was measured at other places. Other three places where we measured acceleration due to gravity were Bear Canyon & Snyder, Sabino Canyon, and at Wilmot and Golf Links Road.

Photo-1: @ Bear Canyon and Snyder

Photo-2: @ Sabino Canyon

Photo-3: @ Wilmot and Golf Links

Acceleration due to gravity was first measured at the hub and then at the three different places simultaneously. Deviation in value of "g" compared to that in hub gives the change. Absolute gravity measurement at the hubs were done at certain intervals using the absolute gravity meter.

Photo-4: Absolute Gravity Meter

Second measurement was again done in all the three places almost within one hour. Before each measurement, we needed to calibrate the gravity meter at the hub. Gravity meter was used to measure acceleration due to gravity at each place and it was measured in mgal. (Gal referred as "galileo" is equal to 1 centimeter per second squared source).This measurement is a field work for a project at USGS Arizona Water Science Center which is studying the amount of aquifer storage in Tucson.

Photo-5: Tucson water under concern

Ground water depletion and land subsidence are said to be occurring in Tucson. So, this study is tended to make sure that the average annual aquifer storage change does not become negative denoting that ground water has undergone depletion. This aquifer storage loss can cause damage to infrastructure due to land subsidence. The project going on is based on the fact that gravity is affected by mass and distance - mass change being the change in water table and distance change being the land subsidence. Thus by removing the effect of change in distance, changes in gravity is used to measure changes in aquifer storage.

A related study dealing on land subsidence and aquifer system compaction in south central Tucson was done between 1987 to 2005, report of which can be accessed from here.

Measuring Erosion Rates - Cascabel Watershed

This post also deals about my trip to Cascabel Watershed on 7th and 8th of November 2009. As mentioned in my earlier post, Cascabel Watersheds are located in the Malpai Borderlands in the eastern part of the Coronado National Forest on western edge of the Animas Valley along the United States-Mexico border. The Malpai Borderlands are found within, and are representative of, the larger Southwestern Borderlands region. Cascabel Watersheds (total area 451 acres) include twelve different watersheds ranging from about 20 to almost 60 acres in size. Our study covered 7 of the total 12 watersheds within Cascabel Watersheds.

Photo-1: One of the 7 watersheds

In this post, I want to describe how I helped my group in estimating erosion rates from the watershed. The watersheds have varying slope so it was obvious that erosion takes place in varying rates.

Photo-2: Slopes at varying degree

In each watershed erosion was measured in every 3 points along the transects. In each of these points, there was a pin within the ground.

Photo-3: Erosion/Deposition Pin

We used a metal detector to detect the point.

Photo-4: Metal Detector

Then the soil level above or below the pin head was measured and was compared with similar measurement done in past years. If it showed that soil level was below the past measurements, it showed erosion and if soil was found above the last measurement, it detects deposition.

The method is simple and easy to implement in the field. Though there can be errors like in detecting the pin as it can be displaced in the field or the measurement of soil level might not be quite accurate. But there is no doubt that this method gives a relative measure of erosion and deposition going on in the watershed that contributes in making management implications for best management practices.

Ground Cover Estimates - Cascabel Watershed

It was on my weekend during 7th and 8th November, 2009 when I joined a group from UofA to Cascabel Watersheds. This watershed is an aggregate of twelve small watersheds on the eastern side of the Peloncillo Mountains in the south-western New Mexico. The area is also identified as Malpai Borderlands in the eastern part of Coronado National Forest, on the western edge of the Animas Valley along the United States-Mexico border.

Photo-1: Cascabel Watersheds

These watersheds, ranging from about 20 to almost 60 acres in size, were established by the Rocky Mountain Research Stations, U.S. Forest Service and its cooperators to evaluate the impacts of prescribed burning on the ecological and hydrologic characteristics of the oak savannas in the region. The aggregate area of these watersheds, called the Cascabel Watersheds, is 451 acres. Each of the Cascabel Watersheds contain between 35 and 45 permanent sample plots that were established along transects located perpendicular to the main stream channel and situated from ridge to ridge. The intervals between the sample plots vary depending on the size and configuration of the watershed under sampling.

I helped the group basically measuring the ground cover and erosion rates. This posting describes about the ground cover measurement. We covered 7 of the total 12 watersheds during this visit.

Photo-2: One of the 7 watersheds

Percentage of plant material, litter, bare soil (including cobble, gravel, and stones), and bedrock on the watershed gives a prediction of hill-slope erosion rates. In each watershed, sample pins were located at certain intervals in different transects. They were symbolized by blue flagging in the field.

Photo-3: Blue Flaggings locating Sample Pin

First the pin was identified. At a distance of 8 feet due north from the pin, a point was noted down as hub.Then first measurement was done directly towards the north of this hub with a quadrat of 12 inch by 18 inch, placing the 12" side facing north. A second measurement at the same pin was made at 3 feet distance and 120 degree from the hub; and a third measurement was done at 3 feet distance and 240 degree from the hub. Thus, three plots were created in each pin along the transects.

Photo-4: Sampling Plots at each Pin

In each sampling plot percentage cover of bare soil, bed rock, litter and plant materials were noted down. This was a relative measurement in terms of how much percentage of the area within the quadrat is covered by bare soil, bed rock, litter and plant materials.

Photo-5: Cover Estimator

The ground cover condition represents a "baseline" for oak savannas of the region. In addition to that, percentage of bare soil and bed rock in comparison to litter and plant materials help in estimating erosion conditions in the area. Vegetative characteristics are good estimates of the capacity of livestock production, quality of wildlife habitats for food and cover, or water related resources.

I chose to join this group as it was a good opportunity to see the south-western watersheds. I had good time understanding the ecological conditions of the watersheds.

Adaptation - learnt from nature - Charleston Crossing

This post is a brief description on how vegetation show their natural adaptation with respect to water resources. On a short tour to Walnut Gulch and San Pedro (same as in earlier post), we stopped by Charleston Crossing. We walked beside the river for some time and took a good observation about the area. It was a small channel with different plants along its either sides. An interesting thing was that there were three plants primarily present in special strata (Photo-1, Photo-2).

Photo-1: Water Channel


Photo-2: Small trees in first line is willow
followed by larger cotton trees and mesquite at the back

First layer of species beside the water channel was Willow trees. Then came the cotton trees and then the Mesquite. It was not an artificial plantation.

Photo-3: Willow trees understorey to cotton trees

Photo-4: Mesquite trees lie farthest to water channel

Willow tree needs much more water and it does not have a long root to get water from higher depth so it was found nearer to the channel. Cotton tree requires less wet habitat compared to willow so was found farther from water channel.

Mesquite is adaptable to drier areas so it is found much farther from the water body. This adaptation of mesquite can also be justified with response to its root system. We could see that mesquite had a long tap root and many lateral roots. The lateral roots help plant to spread on the ground surface.

Photo-5: Mesquite Roots

On absence of water, willow trees are the first to dry up followed by cotton trees. Mesquite is the last to dry which is supported by the long tap roots that go deep into the soil and fulfill water need for the plant.

It is just a normal behavior of plants which we can see commonly in nature but it is interesting to highlight here that these natural adaptations are affected by presence of natural resources, here it is water body.

Measuring hyro & metereo parameters - Walnut Gulch

It was an early morning on October 27th, 2009 that I joined a small tour to Walnut Gulch and San Pedro with David C. Goodrich (Research Hydraulic Engineer, USDA-ARS) and Stephen Miller (student, UOA). Walnut Gulch is an experimental watershed at Tombstone, Arizona. It is taken as an outdoor laboratory for the Southwest Watershed Research Center (SWRC) program of USDA-ARS (United States Department of Agriculture - Agriculture Research Services).

Our trip started at 6 am in the morning. In around 1.5 hrs we reached the field office of USDA at Walnut Gulch experimental watershed. We were first given few introductory information about the different works done by USDA at the site.

Photo-1: Walnut Gulch - a glance

Photo-2: Activities at Walnut Gulch

Then Dave described us about how different hydrological and meteorological parameters were being measured regularly. An interesting thing to be noticed was how analogical methods of measurement were being substituted by digital measures with time. As in Photo-3, the cylindrical rain gauge is supplemented by the squared metallic strip on the ground. It helps in measuring the precipitation.

Photo-3: Rain Gauge

The circular apparatus in Photo-4 measures evaporation rate. As shown in the photo, effect of wind on evaporation is also taken into account. Rate of evaporation is measured by the change in water level in the small triangulated feature inside water body.

Photo-4: Measurement of evaporation

The apparatus shown in Photo-5 measures CO2 flux. Since all these apparatus are attached to the computers, digital measure of all parameters are obtained directly and instantly.

Photo-5: Measurement of CO2 flux

After the informative introduction, we moved to Flume 6 of the Walnut Gulch where we saw how sediment flow rate is measured.

Photo-6: Flume 6

The concreted area is made for measuring actual amount of deposit collected. Sediment deposited is now being recorded using sensors indicated by yellow markings in Photo 7.

Photo-7: Way for Sediment

Initially, the metal shown in Photo-8 was used to collect sediments within the flow and measured.

Photo 8: Metal collecting Sediment

Sediment recorded by the sensors is used to measure the sedimentation rate electronically. The video below describes how the recording works directly.

It was really an informative trip. Though not much to be done by myself, it was my first field exposure in AZ. I found it fruitful and came across how some important measures of hydrological parameters are being collected from the field.

My sincere thanks to David C. Goodrich and Stephen Miller for the opportunity and wonderful company.

Dilution is Pollution's Solution - WMG

I spent my Saturday morning on 24rth October, 2009 volunteering for the Watershed Management Group (WMG). WMG had organized an workshop at the 1325 East 8th Street.

WMG was interested in Tucson washes and watersheds. It was currently working in the Rincon Heights neighborhood to provide water quality education ad improvement. Fund for the program was provided by the Arizona Department of Environmental Quality. The major focus of the project was to reduce "non-point source" pollution - that refers to pollution from dispersed sources such as pet waste, grease, households, lawns, sediments, lawn waste etc.

The workshop was intended to empower local residents on adapting Best Management Practices (BMPs) for stormwater quality. The workshop demonstrated on installing bioretention basins, berms, curb cuts and infiltration trenches. Storm water is taken to be an important problem throughout Tucson. The Rincon Heights neighborhood is an area within Campbell at the east, Broadway at the south, Park Ave at the west and the Sixth Street at the north. The area is seen completely inundated during rainfall. So, at various spots WMG had built bioretention basins.

For the basins, we dug ditches of different sizes at 2 ft. distances from the street. Then strong rocks were used to support the wall of the ditches. Water flow towards few ditches was directed through cut curbs.

Ditches - a glance

Some have cut curbs that direct water from streets to flow into the ditch while the other types without cut curbs serve to direct water from side walks.

Ditch with cut curb

Ditch without cut curb

The cut curves are intended just to make small shallow or eddies besides the usual flow of water in streets. In eddies water moves in circular motion thus no danger of scouring as well as it facilitates water retention by the soil on either sides of the street. Care was taken that it does not turn into small channels. These cut curbs were also lined by small rocks so that it can reduce water velocity of the flowing water and thus reduce soil scouring.

Cut curb - to direct water into ditch

While in other ditches water from side walks was directed just by making the surface slopy towards the ditch. When the ditch was ready, it was filled with gravels.

Ditch being filled with gravel

Then we planted plants of different varieties native to Tucson climate. The area gets much drier during the summer and when it rains it gets fully flooded. So, plants were chosen such that they can tolerate temperature extremes of dryness as well as floods. Some of the plants used were Ironwood, Sotol, Humming Bird Trumpet, Flat Top Buckweed, Triangle Leaf Bursage, Ocotillo, Brittle Brush etc.

Dry-loving plants were planted at the upper level and plants adaptive to watery lands were planted at the lower surface in the ditch.

Ditch view after plantation - I

Ditch view after plantation - I

Compost manure was put at the base of every plant to facilitate growth. The ditch was then completely covered by mulch up to 4-6 inches to reduce evapotranspiration.

Mulch Cover

This kind of ditches/bioretention basins are made up of locally available natural resources, cheap to construct and people do not need special knowledge or skill to work for it. So, it is highly useful and in turn reduces erosion by storm water. Storm water as well as surface water when get directed to small ditches while flowing through the main street during heavy rain, it reduces water velocity and thus its strength to carry soil on its way. Besides, the storm water gets re-directed towards the ditches before reaching their respective wash. The wastes instead of getting deposited in the wash, are diluted to different areas from where they are absorbed by the ground. This facilitates retention through the soil surface and thus helps in reducing the extent of pollution as well. If the wastes end up in the washes, it would obviously increase the pollution concentration but absorption of wastes at different ground surface facilitated by the eddies has diluted the pollution.

I joined the workshop to get introduced with a group working in watershed issues. The workshop helped me learn the rainwater harvesting technique practically which we usually read in books and lectures. If there is a will, we can make our way locally and easily wihout any bigger investment. It was great fun working with them. I look forward for working with the WMG again in future !!

Activities by WMG can be accessed from here.