Dr_Groeger: Hi! It's a pleasure to be here and to talk to you today.

Dr_Groeger: Exotic species are organisms that have evolved in other areas of the world and have somehow accidentally or intentionally been transported into Texas. We have a number of examples of very destructive exotic species in Texas. Where I'm at, here in San Marcos on the San Marcos River, we have constant temperatures year around, we have a number of tropical exotic species that have come from areas of Africa, South America, and Asia. When those tropical species get in a new habitat like Texas, a lot of times there is very little control on their growth. And, for example, we have a number of plant species here on the San Marcos River and the Guadalupe River, and these plants are growing at high rates and forcing out natural plants that occur in those rivers.

Dr_Groeger: One of the reasons water standards are not uniform is because Texas surface waters are classified as different quality waters, for how they can be used. Part of this would be natural, because naturally, even if no people were in Texas, the qualities of these waters would be different, due to the local climate and geology. Also, the different population concentrations within Texas also have a lot to do with the quality of those waters.

Dr_Groeger: A lot of our controls of exotic plants are not very effective, and a lot of these exotic plants are very, very hard to control. One of the best things we can do to control these plants is to be sure that we do not spread them throughout the state, and if you go around to a number of the reservoirs around the state, a lot of times you will see signs that say to check for certain plants attached to your boat to be sure you don't haul those plants from one lake to another. A lot of times the way these plants are spread from lake to lake or from river basin to river basin within Texas are by boaters. And, so very commonly the very best way to fight these plants that grow so rapidly is to be sure that we don't help in the spread of those plants.

Dr_Groeger: Very commonly we cannot kill these exotics without harming the natural species that are there. So as we just talked about in the last question, a lot of times our best control is to be sure that we don't spread these exotics. One technique which has been used on a number of exotic plants--and some of this research is going on or being discussed for Texas--is actually importing exotic organisms that will actually feed on these exotic plants. So we would actually be importing an organism that has evolved to feed on and control these plants.

Dr_Groeger: If you mean exotic plants, which occur within the water, a lot of times the quantity of water is not a question for those plants. Sometimes increased flows can help to eliminate plants. We probably do not have good enough control of water in Texas or enough water in Texas for this to be a very feasible control strategy for eliminating exotic plants. There are some exotic plant problems on the Guadalupe River, in some reservoirs downstream of New Braunfels, Texas, two years ago. In October of 1998 there was a very large flood on this river, and that flood was able to wash many, many of these exotic plants, flush them out of the reservoirs. The following summer the exotic plant problem was much, much less.

Dr_Groeger: One plant I'm thinking of which is a very bad pest plant, is called water hyacinth. It is a tropical plant that grows on the surface where it's roots hang down into the water, but its leaves are up in the air. This is a very bad pest plant. There are some other plants that are similar to this. Many of these exotic plants have been introduced into the United States through people buying plants for their fish aquariums. A lot of times, then, when a person would clean out their aquarium, they would throw out their plants in the local rivers or reservoirs. And so, many of the exotic species that you find in Texas or the United States have come from people dumping them from their homes back into nature. And it's very important that if you have an aquarium at home with fish and plants in there that you don't let them out into nature if you're not sure if they are found in the local ecosystems.

Dr_Groeger: I'm presuming you mean of the potential environmental effects that NAFTA will have on Texas water resources. I think, as we look at the future of Texas from a water standpoint, our biggest long-term water problem will actually be the quantity of water. One of the things that will result from NAFTA is that NAFTA will increase population growth in Texas, and so with more people living in Texas, there is going to be more stress and strain on water resources. The state is going to need more water for the new people coming into the state to drink and live on. So I think the major problem with NAFTA will be one more factor in the state that is causing population to grow. The additional traffic through the state, all the trucks coming up and going down into Mexico, and the building of additional roads, will also have some negative effects on Texas waters.

Dr_Groeger: Because all ground waters have at one time come from the atmosphere, there certainly is some exposure to things that are going on in the atmosphere or the surface that can influence that water. If the water is very hard, there are techniques for making it softer, though I do not believe these are filtration techniques.

Dr_Groeger: The process of desalinization as it exists now is used in certain parts of the world for drinking water. Desalinization is a very expensive process, which uses a great deal of energy. Certain countries that are located in desert climates, and these are countries that tend to be richer countries, like some of the oil countries found in the Mid-East and certain parts of Israel, get some of their water from desalinization of oceanic water. For the most part we look at this, as the technology exists now, as a very, very expensive way to get fresh water. So what many people are hoping for is that technological breakthroughs in the future will make the price of desalinating water much lower.

Dr_Groeger: Yes, that's a very good question. Increases in air pollution can have a very large effect on the quality of water that we find in our rivers or in our groundwater. One of the most well known effects that you see is called acid rain, or acid precipitation. Smoke is generated from car engines or power plants that give us heat or light in our houses. That smoke, from those burning processes, is up in the sky. When the rain comes through the smoke, particles of that smoke cause the rain to become more acidic. This acid rain, in certain parts of the United States, and especially in Northern Europe, has causes many of the lakes in those regions to become more acidic. And in the worst cases, almost all the fish in those lakes have died. That is probably the best-known effect of air pollution having impact on surface waters. There are a number of other impacts that can come from air pollution and water quality,

Dr_Groeger: Yes, that's a very good question. Some of this answer will be speculative because we don't know the exact results. One of these potentially most important influences that global warming can have on Texas is the possibility that it may make Texas more drier, essentially that less rain will fall on the state. Now I should add here that there is a possibility that the greenhouse effect might increase rainfall in Texas. Scientists are not sure if Texas will become drier or wetter, though most think that it will probably become drier. Since Texas already has a potentially severe shortage of water, and the population of the state, the human population of the state is increasing, if the greenhouse effect causes Texas to become drier, that would be a very negative effect. One other effect we see locally here is that for about the last ten years we have had very warm winters in Central Texas. One of the effects that has is it makes the bottom waters of our reservoirs much warmer during the summer and that's not good for a lot of fish who live in those reservoirs.

Dr_Groeger: I'm not sure what unorthodox method of extraction you are referring to, but there are a number of proposals that talk about cross-river basin transfer, or inter-basin transfer, which would mean either the piping or diversion of water from one river system to another river system, or the pumping of ground water in one area into another drainage area. Some of these projects are already going on in Texas. For example, the city of Corpus Christi is in a very dry basin, and has a very severe shortage of water, and some of the water they receive comes from another river basin. I feel that it is inevitable that much more of this will happen in Texas. Because of our large centers of population, we don't know the effects of these inter-basin transfers, but there can potentially be many problems from them.

Dr_Groeger: No, certainly not. One thing I would say, Texas is not water rich, and we don't have the luxury of being able to pollute water in low population areas. There are areas of the world you could make an argument that it would be less important to protect the quality of those waters because it won't affect humans, but I think we should be very careful, and not relax our standards of water quality for remote regions. I think we have come to a point in time, in the history of the human race, that we can't afford to be degrading our environment without very, very good reasons.

Dr_Groeger: I interpret this question to be referring to Texas waters in general, and I think our biggest threat in Texas is the actual quantity of water in Texas. Humans are putting such stress on the water supplies, in other words either taking the surface waters, taking ground waters that humans are becoming responsible for drying up many of our ground water aquifers, our reservoirs, and our rivers. And one of the results of this is very harsh conditions for the aquatic organisms that live in these rivers and reservoirs. Another concern here is that the fish and shrimp that live in the Gulf of Mexico are dependent on river flow coming into the Gulf from Texas. As Texans dry up rivers in Texas, the Gulf of Mexico is not getting enough water from the state either.

Dr_Groeger: The number of chemical tests we can do on water is probably in the thousands of different methods. Some of the most important methods of determining water quality should always include a measure of dissolved oxygen. Dissolved oxygen is the number one characteristic of water that people think of when they talk about water quality. Another measurement, which I think is very important in Texas, is some measure of the total dissolved constituents that are in the water. That could be a TDS measurement, which stands for Total Dissolved Solids. Another similar test, which tells you very similar property of water, is called the conductivity test. These tests are important in the state of Texas because as you go throughout the state you see a great variation in different parts of the state, and so these tests will give you information on local climate and geology influences on the water quality.

Dr_Groeger: Ph is another chemical test that is very commonly done; though I don't think it is as important as those first two. Other chemical tests that can be very important are the measurements of nutrients in the water; for example, nitrogen and phosphorous measurements, or the various forms of those nutrients.

Dr_Groeger: In certain local regions, other tests might also be very important. For example, iron measurements may be very important in certain well water where iron concentrations can be very high. Measurement of specific ions sometimes can also be very important in figuring out the quality of water.

Dr_Groeger: Other tests, which are technically biological types of tests, would include the measurement of certain types of bacteria in the water. One of the most important considerations for water quality that people swim in or that will become drinking water is the different types and numbers of bacteria that you find in those waters. So those are probably the most important tests that you would perform on water to determine water quality.

Dr_Groeger: That's a very good question, and if you have concerns about your own drinking water, there are usually laboratories that do water quality testing somewhere in the local area. Very commonly, for a reasonable price, you can have your water tested. Just yesterday I helped sample water in a house in a nearby town where there was some concern of sewage contamination in their drinking water. In this case, for a price of about ten dollars, a bacterial test is being run on that water to see if there are sewage bacteria coming into that water.

Dr_Groeger: The most common technique for purifying water is to add chlorine gas. The chlorine is added in low concentrations, and it's a very effective chemical agent for killing bacteria.

Dr_Groeger: Fecal coliforms certainly can be a problem at times. One of the times to expect high fecal coliforms is after storm events. Many of the people that are listening to this have probably, or may have, taken bacterial samples, and found very high bacteria numbers associated with storms. I swim a lot in the San Marcos River, and one thing I have noticed, if I'm not careful, is that ear infections are much more common after storms than when things have been drier. So fecal coliforms can be a problem in Texas. They are higher after storms. Fecal coliforms also tend to be higher around areas where you have a lot of people living; also they are very high in waters where you have a lot of cattle in the area.

Dr_Groeger: Chlorine probably has no negative effects on humans other than sometimes the chlorine taste you get. When chlorinated water is dumped into rivers it can potentially kill fish, and probably has some effect on local plants, if the chlorine concentrations are too high. Some sewage plants actually dechlorinate water before it is dumped back in the river, and some don't. So yes, there can be some negatives associated with chlorinating water. If you have an aquarium at home, very commonly one of the things they tell you is if you are going to fill it up with tap water, you want to let the water sit for a day, and just as the water sits, the chlorine, which is actually a gas, will leave that water, and then be no threat to any fish you would put in the aquarium.

Dr_Groeger: Well, that's a good question, and I'll answer it the best I can. I would say yes, they probably are, when you consider the costs involved. We addressed this in one of the earlier questions, that after storms, bacteria concentrations can be very high. If you live in the Austin area, that is commonly when Barton Springs becomes closed. It is due to bacteria concentrations associated with high storm flows. So, Texas, I think, in general, is doing a pretty good job in monitoring the water for bacteria.

Dr_Groeger: That's a very interesting observation. My guess would be what is causing the algal blooms you are seeing is that during those winter months the leaves in the overhead trees, have of course dropped off, and so in January and February you have a lot more sunlight which is reaching the stream, and the algae can grow much better at that time. As the season shifts into March and April, and the leaves start to come back onto the trees, the streams become shaded, or very dark, and it's much harder for the algae to grow. So my guess is, that is what is causing the seasonal blooms of algae that you are seeing.

Dr_Groeger: If you are talking about actually losing water flow to your house, as might occur when a water pipe breaks or for example during a hurricane, sometimes water supplies can be closed down. I think one of the best ways to store water is if your refrigerator is still working you could fill containers and put as many of those in the refrigerator as you can. The bathtub is also another place to store water. Sometimes during large hurricanes, or other events which might damage local water supply systems, local authorities will suggest to you that you boil any water before you drink it. The reason for boiling is there might be bacterial contamination. So bathtub is one place that you can store water quite safely.

Dr_Groeger: I think this type of data can be very valuable. And it is possible there may be ways to use it more efficiently. One thing I would like to stress, and this may be hard for somebody who's only been working with a volunteer program for a year or two, is that a lot of times the data, when it's looked over periods of five or ten or twenty years, certain trends become very obvious. A lot of times looking at the data just over short periods it is very hard to interpret or draw conclusions from. The volunteer monitoring data can be used to try to find specific problems which arise locally. And I would just like to stress that it is important to be patient when you collect data. The data now tends to be stored and kept in electronic forms, where it is much easier to look at long-term results of local efforts.

Dr_Groeger: Well, one of the trends, which we see very clearly in Central Texas, is a eutrophication of the rivers. I need to define this term. Eutrophication is essentially increased plant growth caused by increased nutrients coming into the rivers. The increased eutrophication in Central Texas is very clearly associated with areas of increased human population growth. One of the trends we see is that out on the Edwards plateau, the rivers drain towards the east, and the water quality out on the plateau tends to be very high, and as these rivers flow off the Edwards plateau, and through population centers through the I-35 corridor, the rivers become greatly enriched with nutrients. And plant growth in the downstream rivers is much higher. So one of the clear trends in this degradation of water quality associated with increasing human population.

Dr_Groeger: If you've got a pond on your own property it represents a wonderful place to do some of your own testing. Some of the things of interest in a pond like this would be what kind of fish you have in the pond, and if you want to develop the pond into a fishing pond, the different types of fishes that you might have in a pond like that can have a really large effect on the water quality of a pond. For example, if you have carp, or goldfish in your pond, it is very common that the water is very turbid, (where you have a lot of particles in the water) and sunlight does not penetrate very deeply into the water. If you have other types of fish, like bluegills or bass, for example, the water will tend to be clear. If this is a pond where you have a lot of cows on your property the water tends to be cloudier, because the cows walking in the pond would suspend the particles back in the water. There might be some things that you could add to your pond but I really can't answer that without knowing more information about it.

Dr_Groeger: That's an excellent question, and it's important to consider how your sampling site compares to other sites. One characteristic that you can see in Central Texas rivers, if you go up on the Edwards plateau, where the river channels tend to be cut into limestone, the streams tend to be very clear. If you go down off the Edwards plateau, off towards the Gulf of Mexico, the rivers are flowing over looser soils. And those rivers will tend to pick up more particles, and the rivers tend to become more turbid. So, when we have rivers that are closer to the Gulf, that higher turbidity is partly natural, and it's not necessarily a sign of the effects of humans. Another thing to consider on these locations on the river is if the location is upstream or downstream of certain areas that you'd expect may affect the water quality. For example, as a river or stream flows through a town, the upstream part of the river almost always has higher water quality than a site on the river that is downstream of the town, because human activity in the town has a negative impact on the water quality of the river. So, location of your sampling sites is a very important consideration when you try to figure out what your monitoring data means.

Dr_Groeger: That's an excellent question, and yes, certain types of algae can be associated with different types of nutrients. For example, some of the worst problems associated with algal blooms come from when the algae are blue-green algae, or, another term for blue-green algae is cyanobacteria. Some of these cyanobacteria are capable of fixing their own nitrogen essentially from the atmosphere. So these blue-green algal blooms are associated with waters that have very low concentrations of nitrogen. But if there are high concentrations of these algae, it may be a sign that there is a very high concentration of phosphorous. Cyanobacteria blooms, which are most associated with bad water quality, at the worst can cause toxic reactions that may kill cows drinking the water; or in human drinking supplies, may cause mass cases of diarrhea in some towns that draw their

Dr_Groeger: That's a very good question, and of course it depends on what time frame you are considering. Possibly this summer, the Edwards aquifer levels could get very low -possibly to disastrously low levels, depending on our rainfall. In the long-term, it is hard to be optimistic about the levels of the Edwards aquifer because of all the demands for water we have in Central Texas. One of the things that will happen, as the levels of the Edwards aquifers fall is, if they fall far enough, the Comal River will go dry, as it did in 1956. And eventually, if the levels fall far enough, the San Marcos River will also go dry. And this would be an environmental disaster. So hopefully, we will get enough rain, at least in the short-term, to keep these rivers happy and healthy.

Dr_Groeger: The biggest type of non-point pollution is associated with agricultural land use. And I think the most intensive non-point pollution is going to be associated with plowing the ground and row cropping, and the fertilizers and pesticides that are associated with that type of farming. So the influence of non-point pollution in Texas tends to be much higher in river basins that have a lot of agricultural land use and less of a problem where you have less agriculture. My guess is that the highest, or most important source, of point pollution, is associated with towns and cities, or in other words, where the people are. This also tends to be where you have your highest industrial pollution point sources.

Dr_Groeger: That's a really good question, and I think the answer, as far as my expertise, is no. Though there are a lot of groups that are helping in this process. And I think one example is the Internet, and actually, the very sites that you are reading this answer off of. There are a lot of groups in Texas, made up of both the public and of educators, and people that are very interested in the environment, which are making many efforts to educate the public to environmental concerns.

Dr_Groeger: Probably the best way of decreasing trash in rivers is through personal habits. Don't throw any loose trash out, because anything you might throw on the road, or out in the grass, will tend to end up in the local rivers and lakes. Also, educate people to the fact that there are proper places where we get rid of our solid trash, and recycle parts of our trash that are recyclable.

Dr_Groeger: That's also a very good question. The Lower Colorado River Authority, or LCRA, has just issued a report on that. I actually have it in my hand. I was able to help a little bit with this. One of the things that they found is that the quality of the river downstream of Austin has increased over the last twelve or thirteen years. This is associated with better treatment of the sewage being released by the City of Austin. So that is the positive part of what's going on in the Colorado River. Another trend that they have noticed is that the Highland Lakes are becoming less clear or are becoming eutrophied, and so that is a negative aspect of water quality of the Colorado River.

Dr_Groeger: I think that all the environmental problems we see in the world are either directly or indirectly tied to the increase in human population. The population of the state of Texas is projected to double within the next forty to fifty years. And so the effects of that population growth will probably be disastrous for the state of Texas, and especially for its water resources. As we have discussed in some of the earlier questions, the increased population will put a tremendous stress on the quantity of water in Texas, so there will be a tendency for Texas rivers to have much less flow in the future. One of the things that helps preserve water quality in rivers is the flow, and as you decrease the amount of water flowing through these rivers, water quality will tend to decrease. Also, as the human population increases, many of the types of pollutants we put in the rivers, and the most obvious example is sewage, will increase. So from the standpoint of decreasing water and increasing pollution the future looks bleak unless students that are out there today do their best to help change this situation.

Dr_Groeger: The City of Austin appears to be one of the better places in Central Texas to be, as far as water goes, because the Colorado River does seem to be quite ample, at least for the projected next fifty years, to supply the City of Austin. Many other cities in Texas do not have as clear an outlook on the future as to where their water will come from. So Austin is in pretty good shape.

Dr_Groeger: From what I have seen, working with most of the volunteer groups, they are doing most of the parameters that are of the most interest. This obviously includes dissolved oxygen, sometimes measurements of conductivity, or TDS, or salinity, and those three are all closely related, a lot of times Ph is measured. Many groups have now gone to where they measure bacteria concentrations within the water, so that is a very good thing to have. Some of the volunteer groups have gone to monitoring biological characteristics of the water. I know also some groups do nutrient measurements, for example nitrates and phosphates, and these are very useful parameters.

Dr_Groeger: One thing I cannot stress too much, and this is one thing I try to stress to all my students, when you go out to monitor the river, it is very important that you note the common sense types of observations you can easily make. One example would be is if there has just been a recent rainfall, and if the visual quality of the water looks different, this will have a major effect on your data. Sometimes if it's been dry for a very long time, the characteristics of your sampling site may be very different than during a wet year. It might be very important if it's a sunny day or a cloudy day, or if you are sampling early in the morning or late in the afternoon. These types of observations often don't have clear numbers associated with them, like a test for dissolved oxygen does, but they can be very important in interpreting the meaning of your data.

Dr_Groeger: My only answer would be that I'm not sure what you are testing, relative to what some of the other schools are testing. The techniques follow standard methods, so the types of things you are testing are probably measured in many other schools also.

Dr_Groeger: If there are regular places where people go swimming, it is probably safe to swim there, unless the City of Austin is giving warnings out. They may close swimming areas for a day or two after storms, and this would be associated with mostly bacteria washing in from the city associated with that storm. I do not live in Austin, so I do not know the exact places where people might go swimming, and what to expect on that lake.

Dr_Groeger: In many lakes where there is a lot of fishing, humans can have a large impact on decreasing the number of fish found in the lake. So fisherman can have a large impact on the aquatic ecosystem. Of course, Texas Parks and Wildlife workers stock many of these lakes, or add fish back to many of these lakes, very commonly. And so that will keep the number of fish high.

Dr_Groeger: This will vary in different regions. But, for example, certain types of fish, for example, certain types of trout--we don't have many types of trout in Texas, but certain types of trout are indicators of very high oxygen concentrations. One indication of high water quality commonly is a high diversity of organisms found in the water. It is probably easier to name some indicators of poor water quality than it is to name indicators of good water quality. Very commonly, when you have poor water quality, you have very few types of organisms that you find locally, though you may have very many of those individual organisms.

Dr_Groeger: That's a very good question. Generally, when we shock fish, there is no long-term damage to them. Shocking refers to scientists or fishery workers often collect fish by shooting electrical currents through the water. This stuns the fish and the fish will float up to the surface where they can be very easily collected. Sometimes if the electricity is too high, a few fish are harmed. But generally, we consider this a non-destructive method for sampling fish communities.

Dr_Groeger: Some communities in Texas are now addressing this. One of the best things to do about this problem is to try to keep the addition of impervious cover to a reasonable amount. One of the effects of impervious cover, and essentially what this is referring to, is the building of driveways or buildings or roads on top of soil. And what happens is rainfall that falls on impervious cover does not soak into the ground, but runs off along the roadway or building. One of the effects that this has is that water tends to get into the river very quickly instead of slowly soaking into the ground and reaching the river that way. And as it runs off the road, it takes a lot of pollutants into the river with it. So, one of the best things that we can do in Texas to help control this problem is limit the amount of ground cover, or the area of the drainage basin that can actually be covered by these impervious structures.

Dr_Groeger: I'm a member and I'm on the board of the San Marcos River foundation, which is a citizen's group that helps to protect the San Marcos River. That's one of the things that I personally do is as a citizen.

Dr_Groeger: As students, if you are interested in the environment, and potentially even having a career in environmental field, you can pursue your studies, and read up on the environment, and educate your friends to environmental problems.

Dr_Groeger: Since we do live in a democracy, the people who make decisions about our environmental resources are very sensitive to what the public tells them to do. So ultimately, when our environment is degraded, because of some form of pollution, we are the ones to blame for that.

Dr_Groeger: Okay, this is a very good question. The reason you might, when you are analyzing your data, use percent saturation is that that takes into account the effects of temperature. One of the properties of a liquid like water is that as water warms up, the amount of gas that it can hold decreases. So, for example, if you take a Texas River, let's say a very well mixed Texas river where the water quality is very high, in the wintertime, the dissolved oxygen concentration in that river might be, for example, 8 milligrams per liter. While in the summer, at that same location, dissolved oxygen concentrations may only be 5 milligrams per liter. So, as you warm water, and if it is open to the atmosphere, the quantity of oxygen that it can hold becomes less and less. The idea of using percent saturation numbers, then, is you can compare your winter samples, or your winter data, with your summer data, and it makes those numbers comparable. When I use dissolved oxygen measurements in my own analysis, I use both the concentration of dissolved oxygen, and that's either measured in milligrams per liter or parts per million (ppm) and, the percent saturation also.

Dr_Groeger: Generally, from an education standpoint, probably the best is to take as many science courses as possible, and this will then allow for understanding of the scientific basis of what's going on in your local environment. Training as a student working in the volunteer monitoring groups is very good training, especially if you don't only go out and collect samples, but you also get to work with the data that has been collected. Another potentially very valuable area of experience can be doing science projects that are associated with environmental concerns. If you are in college it can be very helpful to find out what kind of environmental research is going on at that university, and what the global environmental problems are, and either work with researchers or groups that are interested in preserving the environment.

Dr_Groeger: Well, thank you very much for having me, and while some of my answers were somewhat pessimistic about the future, the future is really in your hands. And if you have a strong interest in preserving the environment, and act on those interests, then the future of our planet can, I think, have a happy tomorrow. And thank you very much for having me!